Input: In the case of single-track deposition, complex thermocapillary convection drives gas bubble diffusion, and pore defects cluster along the lateral edge.

deposition

gas

diffusion

defects

pore


Input: In the case of multi-track deposition, surface pore defects were more likely to occur on the last track due to the gravity-driven flow effect that is determined by the track path and overlap.

deposition

surface

defects

overlap

pore


Input: Metal-filled polymers containing micro-powders of highly conductive metals can serve as a starting material to fabricate complex metal structures using economic filament extrusion-based 3D printing and molding methods.

polymers

metals

as

material

metal

filament

fabricate

3D printing

molding


Input: We report our measurements of the thermal conductivity of copper samples prepared using these methods before and after a thermal treatment process.

thermal conductivity

copper

thermal treatment

process


Input: Sintering the samples at 980 ℃ leads to an order of magnitude improvement in thermal conductivity when compared with as-printed or as-molded samples.

Sintering

samples

samples

magnitude

thermal conductivity


Input: Thermal conductivity values of approximately 30 W/mK are achieved using commercially available polymer-copper composite filaments with a copper volume fraction of 0.4.

Thermal conductivity

composite

copper

fraction


Input: Over-sintering the samples at 1080 ℃ further enhances the thermal conductivity by more than two folds, but it leads to uncontrolled shrinkage of the samples.

samples

shrinkage

samples

thermal conductivity


Input: The measured thermal conductivities show a modest decrease with increasing temperatures due to increased electron-phonon scattering rates.

thermal conductivities

temperatures


Input: The experimental data agree well with the thermal conductivity models previously reported for sintered porous metal samples.

experimental data

thermal conductivity

sintered

porous metal


Input: The measured electrical conductivity, Young’ s modulus and yield strength of the present sintered samples are also reported.

electrical conductivity

yield strength

s

sintered

samples


Input: The Electron Beam Melting (EBM) technology enables the manufacturing of new designs and sophisticated geometries.

Electron Beam Melting

EBM

manufacturing

technology

geometries

designs


Input: The process is particularly well suited for the fabrication of lattice structures.

process

fabrication

lattice structures


Input: A standard methodology is presented in order to predict the mechanical response of lattice structures fabricated by EBM.

standard

methodology

mechanical response

fabricated

lattice structures

EBM


Input: The inner and outer structure of single struts produced by EBM was characterized using X-ray tomography.

structure

struts

EBM

X-ray tomography


Input: Struts with a 1 mm diameter and different orientations respect to the build direction were analyzed.

Struts

mm

diameter

orientations

build direction


Input: The geometry discrepancies between the designed and the fabricated strut were highlighted.

geometry

fabricated

designed


Input: Two effects were identified: (i) The produced struts are generally thinner than the designed ones, (ii) Within the produced struts, loads are not transmitted by the entire geometry.

struts

struts

designed

geometry


Input: The elastic response of the strut was assumed to be represented by a circular cylinder with an equivalent diameter.

elastic

strut

be

diameter


Input: The first one is the diameter of an inscribed cylinder whereas the second one is the result of a numerical simulation based on the 3D image of the strut characterized by X-ray tomography.

diameter

3D image

numerical simulation

strut

X-ray tomography


Input: The methodology was then applied to an octet-truss lattice structure.

methodology

lattice structure


Input: The mechanical equivalent diameter obtained by numerical simulation on a 3D image of the strut allows to simulate the “true” properties of the lattice structure by taking into account the manufacturing constraints of the EBM process.

mechanical

diameter

3D image

properties

manufacturing constraints

numerical simulation

strut

lattice structure

EBM


Input: We have investigated the spatial distribution of microstructures of a Co-Cr-Mo alloy rod fabricated by Electron Beam Melting (EBM) method along built height.

spatial distribution

microstructures

alloy

fabricated

Electron Beam Melting

EBM


Input: The topside of the rod is rich in γ-fcc phase and consists of fine grains with high local distortion density.

rod

phase

grains

distortion

density


Input: The bottom part has an ε-hcp single phase and consists of relatively coarser grains with low local distortion density.

phase

grains

distortion

density


Input: The mean grain size increases from 56 μm (at the top of the rod) to 159 μm (at the bottom), and is accompanied by a decrease in the γ-fcc phase fraction.

grain size

rod

phase fraction


Input: As a result, the hardness of the samples, as well as the area fraction of precipitates formed in the samples, increases gradually from top to bottom of the rod, while corrosion resistance is uniformly high throughout the rod almost independently of the location.

As

as

as

precipitates

hardness

samples

samples

corrosion resistance

area

rod

rod


Input: The mechanism behind the formation of phase distribution is discussed in terms of thermodynamic phase stability and kinetics of phase transformation accompanying the thermal history during the post-solidification process.

mechanism

phase

distribution

phase

phase

process


Input: To increase the productivity of Laser Powder Bed Fusion (LPBF), a hull-bulk strategy can be implemented.

productivity

Laser Powder Bed Fusion

LPBF

be


Input: This approach consists in using a high layer thickness in the core of the part, hence reducing the build time, and a low layer thickness in the skin, to maintain a high accuracy and good surface finish.

layer thickness

build time

layer thickness

core

accuracy

surface finish


Input: The present study investigated to what extent this strategy affected the surface roughness, relative density, microstructure and mechanical properties of Ti-6Al-4 V parts.

surface roughness

relative density

microstructure

mechanical properties

Ti-6Al-4 V


Input: Ti-6Al-4 V specimens were built using two distinct sets of process parameters, one optimized for a 90 μm-layer thickness in the bulk and the other for a 30 μm-layer thickness in the hull.

Ti-6Al-4 V

process parameters


Input: In addition to surface roughness and relative density measurements, a thorough microstructure analysis was done using both optical microscopy and SEM.

surface roughness

relative density

microstructure

optical microscopy

SEM


Input: Additionally, EBSD measurements and numerical reconstruction of the parent β grains were performed to evaluate the mesostructure and texture evolution from hull to bulk.

EBSD

reconstruction

grains

evolution

texture


Input: Microhardness measurements and tensile tests were done to assess the effect of the hull-bulk strategy on the mechanical properties.

Microhardness

mechanical properties

tensile tests


Input: The present study demonstrated the possibility of using the hull-bulk strategy to build high-quality Ti-6Al-4 V parts, without impacting their tensile properties, hence increasing the productivity of the process by a geometry-dependent factor, typically ranging between 25% and 100%.

build

Ti-6Al-4 V

tensile properties

productivity

process


Input: In Laser powder bed fusion (L-PBF), metal powders, sensitive to humidity and oxygen, like AlSi10Mg or Ti-6Al-4 V are used as starting material.

Laser powder bed fusion

L-PBF

metal powders

oxygen

Ti-6Al-4 V

as

material


Input: Titanium-based materials are influenced by oxygen and nitrogen due to the formation of oxides and nitrides, respectively.

materials

oxygen

nitrogen

oxides

nitrides


Input: During this research, the oxygen concentration in the build chamber was controlled from 2 ppm to 1000 ppm using an external measurement device.

research

oxygen

build chamber

measurement


Input: Built Ti-6Al-4 V specimens were evaluated regarding their microstructure, hardness, tensile strength, notch toughness, chemical composition and porosity, demonstrating the importance of a stable atmospheric control.

Ti-6Al-4 V

microstructure

chemical composition

hardness

tensile strength

porosity

notch


Input: It could be shown that an increased oxygen concentration in the shielding gas atmosphere leads to an increase of the ultimate tensile strength by 30 MPa and an increased (188.3 ppm) oxygen concentration in the bulk material.

be

oxygen

oxygen

material

gas

MPa

ultimate tensile strength


Input: These results were compared to hot isostatic pressed (HIPed) samples to prevent the influence of porosity.

pressed

samples

porosity


Input: In addition, the fatigue behavior was investigated, revealing increasingly resistant samples when oxygen levels in the atmosphere are lower.

fatigue

samples

oxygen


Input: A concept of body heat flux has been developed to predict part distortion.

heat flux

distortion


Input: Powder-liquid-solid material state transition was simulated via user subroutine.

material

transition


Input: Large tensile residual stress occurs on the top layer of the part.

tensile residual stress

layer


Input: Part distortion was predicted with reasonable accuracy.

distortion

predicted

accuracy


Input: Selective laser melting (SLM) is a promising technology to manufacture functional (end-use) metal parts with complex geometry directly from CAD data.

Selective laser melting

SLM

technology

manufacture

complex geometry

metal

CAD


Input: The process induced high tensile residual stress and part distortion due to the non-uniform heat input during a SLM process would detrimentally affect the part performance.

process

distortion

heat

process

performance

tensile residual stress

SLM


Input: However, it is extremely challenging to predict distortion of a practical SLMed part if each single track is taken into account by using the conventional modeling methods The complex multiphysics phenomenon such as fluid flow in the melt pool, phase transformation during cooling, and resulted anisotropic properties further complicate this issue.

distortion

phase

SLMed

cooling

modeling

as

melt pool

anisotropic


Input: In this study, a temperature-thread multiscale modeling approach has been developed to effectively predict residual stress and part distortion of a twin cantilever.

multiscale modeling

distortion

residual stress

cantilever


Input: An equivalent body heat flux has been proposed from the microscale laser scan model and imported as the “temperature-thread” to the subsequent mesoscale layer hatch model.

heat flux

microscale

mesoscale

model

laser scan

as

layer


Input: The hatched layer is then heated up by the equivalent body heat flux and used as a basic unit to build up the macroscale part in a layer by layer fashion.

layer

build

heat flux

macroscale

layer by layer

fashion

as


Input: The thermal history and residual stress fields of the twin cantilever during the SLM process were simulated.

residual stress

cantilever

SLM

process


Input: The predicted cantilever distortion agrees with the measured data with a reasonable accuracy.

predicted

data

cantilever

accuracy


Input: Open cellular structures fabricated in Ti6Al4V using the electron beam melting (EBM) process have been proposed for tissue scaffolds and low stiffness implants that approximate the properties of bone.

cellular structures

scaffolds

electron beam melting

EBM

process

properties

stiffness

implants

bone


Input: The properties of these structures, regardless of cell geometry, have often been determined through compressive testing, and very few of these studies have investigated the flexural properties.

properties

properties

cell

testing


Input: For certain types of implants that are designed to fill very large segmental defects in appendicular bones, such as those used in limb sparing, compression testing does not provide the necessary insight into the complex loading states typical of bending.

implants

designed

defects

as

compression

bending


Input: In this study, EBM-fabricated Ti6Al4V prismatic bars, populated with rhombic dodecahedron unit cells of various sizes and relative densities, were subjected to four-point flexure tests.

prismatic

unit cells

relative densities

flexure tests


Input: While the results generally follow the power scaling models of Gibson and Ashby, the use of these models as a design tool is limited by machine resolution, particularly when producing structures with small pore sizes required for bone ingrowth.

power

pore sizes

as

design

machine

bone ingrowth


Input: The laser powder bed fusion (LPBF) process can produce parts with complex internal geometries that can not be easily manufactured using a material removal process.

laser powder bed fusion

LPBF

process

manufactured

material removal process

internal geometries

be


Input: However, owing to the different heat transfer efficiencies of a laser melting process, the optimal process parameters are limited to a small range.

heat transfer

process

laser

optimal process

range


Input: This study used galvanometric scanner technology and a diffractive optical element (DOE) to build an experimental multi-spot LPBF system.

technology

experimental

optical element

build

LPBF


Input: An adjustable multi-spot method was used to modulate the temperature field on the powder bed and enhance the processing quality and throughput.

temperature

powder bed

quality

throughput


Input: The results from the synchronized three-spot method using different scanning strategies improved the layer surface roughness Ra by 3.2 μm.

scanning strategies

layer

roughness


Input: Moreover, the scanning time was decreased by 38.1% of the single-spot method.

scanning time


Input: It has been shown that quality of components built using selective laser sintering (SLS) are strongly affected by the thermal history of the building process.

quality

components

selective laser sintering

SLS

building process


Input: Temperature variations of a few degrees across the powder surface can alter the mechanical properties of components and render them unsuitable for their intended purpose.

Temperature

powder

mechanical properties

components


Input: Therefore, to improve the quality of SLS components and ease their adoption into the marketplace, temperature fluctuation issues must be addressed.

quality

SLS

components

temperature

be


Input: Some success has been demonstrated in the past at reducing temperature non-uniformity by improving the heater system that pre-heats the polymer powder prior to sintering with the laser.

temperature

polymer

sintering

laser


Input: This paper will cover a complimentary approach of actively controlling laser fluence on the powder surface based on infrared temperature measurements.

laser

powder

infrared


Input: By controlling the amount of energy input by the laser, a high level of control over the final part temperature can be achieved and uniformity can be improved.

laser

temperature

be

be


Input: This paper will cover development of the feed-forward control system and will present results showing that for constant cross-section specimens, a 45% improvement in ultimate flexural strength standard deviation was achieved.

control system

flexural strength


Input: In the selective laser sintering of polymers, the most widely used powders are based on polyamide 12 (PA12), which is a semi-crystalline polymer.

selective laser sintering

polymers

powders

polyamide 12

polymer


Input: Because the mechanical properties of the printed parts depend largely on the microstructure, knowledge on the crystalline architecture is important.

mechanical properties

microstructure

architecture


Input: We developed a numerical model based on the finite element method to solve the flow, temperature and crystallization kinetics of PA12 powder during sintering using two different geometries.

model

finite element method

crystallization

geometries

temperature

sintering


Input: Our results show that the temperature plays a crucial role in the crystallization kinetics and that simplified 0D calculations can be used to study the crystallization kinetics if the temperature behavior in time at a certain location is known.

temperature

temperature

crystallization

crystallization

be


Input: With our choice of initial and boundary conditions, we found primarily crystals of the α′-phase.

boundary conditions


Input: A model for predicting the thermal response of Inconel® 718 during laser powder-bed fusion processing (LPBF) is developed.

model

fusion

laser

LPBF


Input: The approach includes the pre-placed powder layer in the analysis by initially assigning powder properties to the top layer of elements before restoring the solid properties as the heat source traverses the layer.

powder

powder

elements

as

layer

layer

layer

properties

heat source


Input: Different linear heat inputs are examined by varying both laser power and scan speed.

heat

laser power

scan speed


Input: The effectiveness of the model is demonstrated by comparing the predicted temperatures to in situ experimental thermocouple data gathered during LPBF processing.

effectiveness

model

predicted

in situ

experimental

data

LPBF


Input: The simulated temperatures accurately capture the measured peak temperatures (within 11% error) and temperature trends.

temperatures

temperatures

temperature

accurately

error


Input: The effect of neglecting the pre-placed powder layer in the simulations is also investigated demonstrating that conduction into the powder material should be accounted for in LPBF analyses.

powder

powder material

be

layer

simulations

LPBF


Input: The simulation neglecting the powder predicts temperatures more than 30% higher than the simulation including the powder.

simulation

simulation

powder

powder

temperatures


Input: Four stages were designed to evaluate the surface morphologies of Ti6Al4V SLM parts.

designed

surface morphologies

SLM


Input: The stages focused laser power, scanning speed, hatch spacing and rescanning effects.

laser power

scanning speed

hatch spacing


Input: Processing parameters significantly influenced vertical and top surface properties.

parameters

vertical

surface

properties


Input: The microcracks were noticed at the interfaces of adhered particles and melt pool.

microcracks

particles

melt pool


Input: Viscosity and cooling rate are the key factors to regulate the surface morphology.

Viscosity

cooling rate

surface morphology


Input: The surface morphology of a product plays a crucial role under mechanical loading and chemical environment.

surface morphology

mechanical loading


Input: Surfaces of Selective Laser Melting (SLM) products often contain high roughness, which varies in different planes as well.

Surfaces

Selective Laser Melting

SLM

roughness

as


Input: The authors have explored the surface characteristics of the SLM samples that are influenced by different combinations of laser processing parameters.

surface

samples

laser processing

SLM


Input: The considered processing parameters were Energy Density (ED) and its technological parameters namely laser power, scanning speed and hatch spacing.

parameters

parameters

Energy Density

laser power

scanning speed

hatch spacing

ED


Input: Additionally, a comparison study has been executed by rescanning effects considering melting with low ED and, thereafter, rescanning by the best possible laser processing parameters.

melting

ED

laser processing


Input: The results evidently showed that the surface morphologies differ significantly due to different laser processing parameters.

surface morphologies

laser processing


Input: Eventually, the thermal and physical behavior of materials, such as the viscosity of the melt pool, thermal and physical stability of the melt pool, solidification time, cooling time, shrinkage, capillary effect, surface tension, balling effect, and the amount of melting of a powder particle, influenced the surface properties of the samples, along with unpredictability.

materials

solidification time

shrinkage

capillary effect

surface

properties

samples

as

melt pool

melt pool

powder particle

viscosity

stability

surface tension

cooling

melting


Input: The results showed an interesting correlation between the processing parameters and the occurrence of microcracks on the vertical walls of the specimens caused by the partially melted adhered powder particles.

parameters

microcracks

vertical

melted

powder particles


Input: Acrylonitrile butadiene styrene (ABS) specimens fabricated by fused filament fabrication (FFF) were post treated by acetone, ethyl acetate and their mixed vapour.

Acrylonitrile butadiene styrene

ABS

acetone

fabricated

fused filament fabrication

FFF


Input: The effect of different chemical vapour, exposure time and building orientation on the surface roughness, tensile strength, dimension and weight stability of the ABS specimens were investigated before and after treatment.

exposure

building orientation

weight

surface roughness

tensile strength

stability

dimension

ABS


Input: The results demonstrated that all chemical vapours were capable of improving the surface coarseness of ABS specimens.

surface

ABS


Input: The tensile strength of specimens treated with the acetone or the mixed vapour decreased with increasing the exposure time.

tensile strength

acetone

exposure


Input: The weight of specimens after treatment increased with prolonging the exposure time due to the absorption of the chemical vapours.

weight

exposure

absorption


Input: In this work, polyphenylene sulfide (PPS) was reinforced with a thermotropic liquid crystalline polymer (TLCP) to generate composite filaments for use in Fused Filament Fabrication (FFF).

reinforced

thermotropic liquid crystalline polymer

composite

Fused Filament Fabrication

FFF


Input: Because of non-overlapping processing temperatures, rheology enabled taking the advantage of the dual extrusion technology, which generated nearly continuously reinforced filaments that exhibited a tensile strength and modulus of 155.0 ± 24.2 MPa and 40.4 ± 7.5 GPa, respectively.

temperatures

rheology

tensile strength

GPa

extrusion

reinforced

MPa

filaments


Input: On printing using these filaments, the maximum tensile strength and modulus obtained were 108.5 ± 19.4 MPa and 25.9 ± 1.1 GPa, respectively, higher than the properties reported on using short fiber composites.

filaments

short fiber composites

tensile strength

GPa

MPa

properties


Input: Moreover, the tensile strength was lower, and the tensile modulus was higher in comparison with the reported use of continuous fibers.

tensile strength

tensile

continuous fibers


Input: Additionally, the tensile properties in the print direction were higher than those of compression molded samples.

tensile properties

compression

print

samples


Input: The nearly continuous reinforcement did not restrict the mobility of the printer, unlike the reported performance of the continuously reinforced carbon fiber thermoplastics in FFF.

reinforcement

printer

performance

reinforced

carbon fiber

FFF


Input: This work aims to investigate the influence of the orientation and microtexture of columnar grains on the fatigue crack growth of a Ti-6.5Al-2Zr-Mo-V titanium alloy fabricated by directed energy deposition.

orientation

fatigue crack growth

fabricated

columnar grains

Ti-6.5Al-2Zr-Mo-V titanium alloy

directed energy deposition


Input: In this paper, the fatigue crack growth rate test in three sampling directions in a directed energy deposited Ti-6.5Al-2Zr-Mo-V titanium alloy using compact specimens was carried out.

fatigue crack growth rate

sampling

Ti-6.5Al-2Zr-Mo-V titanium alloy

compact


Input: The crack length was measured visually, and the fatigue crack growth rate of the stable crack growth stage was obtained.

fatigue crack growth rate

crack growth


Input: During the test, the influence of the microstructure on the crack growth was directly observed.

microstructure

crack growth


Input: In addition, the complete crack front shape was indicated on the fracture surface by the marker load technique, and the crack growth behavior was obtained.

fracture

crack growth


Input: An optical microscopy, a scanning electron microscopy and a laser confocal microscopy were used to observe and clarify the influence of the columnar grain boundary on the crack growth behavior and the interaction between the crack front and microstructure.

optical microscopy

scanning electron microscopy

microscopy

laser

columnar grain boundary

crack growth

microstructure


Input: The results show that the fatigue crack growth rate in the three sampling directions is different in the low ΔK region; the columnar grain boundary has no significant effect on the fatigue crack growth behavior, but the columnar grain itself has an effect on the fatigue crack growth behavior, which is indicated by the irregularity of the crack front shape in different columnar grains.

fatigue crack growth rate

sampling

columnar grain boundary

fatigue crack growth

fatigue crack growth

columnar grain

columnar grains


Input: Microhardness testing and electron backscattered diffraction were used to explain the above phenomena based on static and orientation characteristics.

Microhardness

orientation

diffraction


Input: It was found that the microtexture and orientation of the columnar grains are responsible for differences in the crack growth rates, and the orientation of the columnar grains also determines the extent of the difference.

orientation

crack growth

orientation

columnar grains

columnar grains


Input: Multi-scale microstructure of a laser 3D-printed Ni-based superalloy was examined.

microstructure

laser


Input: Elements and precipitates heterogeneously distribute at the cellular scale.

Elements

precipitates

heterogeneously


Input: Cell boundaries are characterized as low angle grain boundaries.

Cell

boundaries

as

grain boundaries


Input: The heterogeneous microstructure of a laser 3D printed Ni-based superalloy was examined at multiple length scales.

heterogeneous

laser

3D printed

length scales


Input: The crystal grains grow in epitaxy with the substrate under the large temperature gradient and high cooling rate.

grains

epitaxy

substrate

temperature gradient

cooling rate


Input: The cell boundaries, decorated with γ/γ′ eutectics, μ-phase precipitates and high density of dislocations, show enrichment of γ′ forming elements and low-angle misorientations.

cell

boundaries

precipitates

elements

density

dislocations

forming


Input: Dislocations trapped in the intra-cellular regions are characterized as statistically stored dislocations with no detectable contribution to lattice curvature, and are the results of the interaction between dislocations and γ′ precipitates.

Dislocations

dislocations

lattice

dislocations

as

precipitates


Input: Unlike conventional powder metallurgy techniques, selective laser melting (SLM) is characterised by its fully melting process and very high heating and cooling rates and little has been known about the influence of powder surface state on the SLM process.

powder metallurgy

selective laser melting

SLM

melting

heating

SLM

cooling rates

powder

process


Input: In this study, the influence of low temperature powder drying on the surface chemistry of Al-12Si powder and its subsequent effect on SLM was investigated in detail by means of an in-depth X-ray photoelectron spectroscopy.

temperature

powder

powder

drying

SLM

surface

chemistry

X-ray photoelectron spectroscopy


Input: An enhanced densification (relative density ≥99%) was achieved in the dried Al-12Si powder compared to the as-received powder.

densification

dried

relative density

powder

powder


Input: This has been attributed to the modification of powder surface by removing a moisture skin during the drying process, which prevents the formation of deleterious oxide and hydroxide during SLM.

powder

oxide

hydroxide

drying

SLM


Input: This study provides important information for achieving high relative density in SLM fabricated metal components from a powder drying aspect.

relative density

SLM

drying

fabricated

components

powder


Input: Selective laser melting (SLM) processed stainless steel usually exhibits an inhomogeneous microstructure in the as-built condition.

Selective laser melting

SLM

processed

microstructure

steel


Input: The effect of powder chemical composition on the microstructural evolution of SLM processed 17-4 PH in the as-built condition was studied.

powder

chemical composition

microstructural evolution

processed

PH

SLM


Input: A path to achieve a fully martensitic 17-4 PH component in the as-built condition by fine-tuning the alloy composition without any post-built heat treatments was demonstrated.

PH

component

alloy

heat treatments


Input: The as-built 17-4 PH phase transformation from δ ferrite to austenite (γ) and subsequently to martensite (α’) was governed by the concentrations of ferrite and austenite stabilizing elements as represented by a chromium to nickel equivalent (Creq/Nieq) value.

PH

ferrite

austenite

martensite

ferrite

austenite

elements

as

chromium

nickel


Input: Electron backscatter diffraction (EBSD) analysis revealed that increase in the WRC-1992 equations based Creq/Nieq value to ≥ 2.65 resulted in coarse δ ferrite grains with a < 100 > preferential crystal orientation along the build direction.

Electron backscatter diffraction

EBSD

ferrite

crystal orientation

build direction


Input: Epitaxial growth of semi-circular and columnar δ ferrite grains accompanied by a marginal volume fraction of retained austenite and transformed martensitic phases was observed.

Epitaxial

ferrite

retained austenite

volume fraction


Input: Retained austenite and transformed martensitic phases exhibited a fine grain structure preferentially along the coarse ferrite grain boundaries.

Retained austenite

ferrite

grain structure

boundaries


Input: EBSD phase composition analysis along with thermodynamic equilibrium modeling implies that a lower Creq/Nieq value promotes martensite formation resulting in a less retained δ ferrite in the as-built condition.

EBSD

composition

equilibrium

martensite

ferrite


Input: The microstructure of as-deposited LAMed 300 M steel is different from that of forgings.

microstructure

steel


Input: Heat accumulation affects the as-deposited microstructure of LAMed 300 M steel.

Heat accumulation

microstructure

steel


Input: After heat treatment, the microstructure of LAMed 300 M steel is refined and uniform.

heat treatment

microstructure

steel


Input: After heat treatment, the impact toughness of LAMed 300 M steel significantly improved.

heat treatment

impact

steel


Input: The crack propagation mechanism of LAMed 300 M steel is revealed by EBSD.

crack propagation

steel

EBSD


Input: Direct manufacturing techniques, such as directed energy deposition (DED), are able to produce complex components efficiently.

Direct manufacturing

deposition

as

DED

components


Input: In this study, microstructure evolution and impact toughness of DED 300M ultra-high strength steel are investigated.

microstructure evolution

impact

DED

strength

steel


Input: The results show that the microstructure of the as-deposited DED 300M ultra-high strength steel is mainly composed of martensite and some blocky bainite.

microstructure

DED

strength

steel

martensite

bainite


Input: The micro-segregation of elements is observed within the interdendritic area.

micro-segregation

elements

area


Input: After heat treatment, the microstructure becomes uniform and consists of martensite and lower bainite.

heat treatment

microstructure

martensite

bainite


Input: The impact toughness of the as-deposited DED 300M ultra-high strength steel is 9 J/cm2, while it is significantly increased to 25 J/cm2 after heat treatment.

impact

DED

heat treatment

strength

steel


Input: Furthermore, it is observed that the fracture mode of the as-deposited sample is quasi-cleavage fracture.

fracture

sample

fracture


Input: During the process of propagation, the main cracks would go across the martensite packet and deflect in the another one, and secondary cracks also deflected in the high-angle grain boundaries.

process

grain boundaries

go

martensite


Input: By contrast, the fracture mode of heat-treated DED 300 M steel is ductile fracture.

fracture

ductile fracture

heat-treated DED

steel


Input: CP-Ti was used to produce SLM RAIs for immediate implantation.

SLM

implantation


Input: Inclination angle affects Sa by determining the powders melted in stairs.

Inclination angle

powders

melted


Input: Dental implant with a consistent Sa was produced with gradient parameters.

Dental

parameters


Input: Vivo experiment showed good osteogenesis with the SLM RAIs in experimental dogs.

experiment

experimental

SLM


Input: Selective laser melting (SLM) is a promising technology for use in “immediate implantation” to quickly fabricate customized dental implants.

Selective laser melting

SLM

implantation

fabricate

technology

dental


Input: However, the implant surface produced using SLM has a high and inconsistent surface roughness, which greatly affects early cell behaviors and osseointegration.

implant

cell

SLM

surface roughness

osseointegration


Input: In this work, samples were produced with different border process parameters and inclination angles.

samples

process parameters

inclination angles


Input: The surface roughness and morphology of the side surfaces were measured and studied.

surface roughness

morphology

surfaces


Input: The results indicate that a large offset value increases surface roughness due to an insufficient energy input, while a small offset increases surface roughness due to an intensified Marangoni convection.

offset

offset

surface roughness

surface roughness


Input: Different inclination angles affect surface roughness due to stair effects and the heat-affected zone.

inclination angles

surface roughness


Input: Based on the above results, a dental implant was fabricated using gradient processing.

dental

fabricated


Input: Compared with the implant fabricated with a single parameter process, the implant processed with gradient parameters had a low and consistent surface roughness.

implant

implant

fabricated

parameter

parameters

surface roughness


Input: An energy balance that describes the transfer of energy is proposed for the laser-based directed energy deposition process.

directed energy deposition process


Input: The partitioning of laser energy was experimentally measured and accurately validated using a special process calorimeter for Ti-6Al-4V and Inconel 625™ alloys.

laser energy

process

accurately

Inconel

alloys


Input: The total energy provided by the laser was partitioned as: the energy directly absorbed by the substrate, the energy absorbed by the powder stream and deposited onto the substrate, the energy reflected from the substrate surface, and the energy reflected or absorbed and lost from the powder stream.

laser

as

substrate

powder

substrate

substrate

powder


Input: Titanium alloy Ti-6Al-4V showed higher overall or bulk absorption than the Inconel 625™ alloy.

Titanium alloy

Inconel

alloy

absorption


Input: Processing with powder resulted in lower laser energy absorption within the substrate than without powder, due to the “shadowing” effect of the powder stream within the beam and loss of energy representing unfused powder.

powder

substrate

powder

powder

powder

laser energy

absorption

beam


Input: During processing at a laser power of approximately 1 kW the total energy absorbed during the deposition process was found to be 42% for the Ti-6Al-4V alloy and 37% for the Inconel 625™ alloy.

laser power

deposition process

be

Ti-6Al-4V alloy

Inconel

alloy


Input: Under these conditions 14% of the total energy was lost by the Ti-6Al-4V unfused powder; whereas only 11% was lost by the Inconel 625™ powder.

powder

Inconel

powder


Input: Cold gas dynamic spray is a cold spray technique for obtaining solid-state surface coating.

gas dynamic

solid-state

coating


Input: Several materials such as metal, metal alloys, composite materials, and polymer have been deposited successfully through cold spray onto a substrate material.

materials

as

metal alloys

composite materials

polymer

substrate material


Input: A number of industrial applications for cold spray have been developed worldwide in the field of aerospace, energy, automobile, biotechnology, and military applications.

industrial

aerospace

automobile

military


Input: In the current study, effects of various processing parameter such as impact velocity, substrate preheating temperature, a combination of different materials and coefficient of friction were used to describe the impact behaviour of ductile materials (copper, Cu, and aluminium, Al) after deposition to find a way of addressing high-strain-rate dynamic problems.

parameter

materials

impact

deposition

dynamic

as

substrate

copper

Cu

aluminium

Al

preheating

coefficient of friction

ductile


Input: The parameters were also used to verify the deposition process for the modelling of cold gas dynamic spray (CGDS) by the Lagrangian approach of finite element analysis.

parameters

gas dynamic

finite element analysis

deposition process

modelling


Input: The results of the analysis (simulation) and that of the published experimental results in the literature correlated well.

simulation

experimental

correlated


Input: The understanding of the impact behaviour using different parameters was evident by the analysis of temperature and equivalent plastic strain (PEEQ).

impact

parameters

temperature

plastic


Input: It was discovered that the deposition process and deformation are largely affected by particle material as compared to the substrate.

deposition process

deformation

particle

material

as

substrate


Input: A lower restitution coefficient was obtained when different materials of varying properties were combined compared to the combination of the same material.

materials

properties

material


Input: Also, the parameters under investigation do not affect the CGDS process individually, as their effects are interrelated.

parameters

process

as


Input: A β titanium alloy, Ti-10V-2Fe-3Al, was selectively laser melted under a modulated pulsed laser mode with different processing conditions.

titanium alloy

laser

pulsed laser


Input: The as-fabricated samples were examined using a range of characterization techniques and properties evaluated through tensile testing.

samples

properties

range

tensile testing


Input: It is shown that with a small powder layer thickness (30 μm), a low laser power and a short exposure time (i.e., low energy density) led to development of fine β columnar grains and widespread cell structures whereas increased laser power and exposure time (i.e., high energy density) resulted in pronounced grain growth, increased texture and significantly decreased cell structures.

powder

layer thickness

laser power

energy density

laser power

energy density

exposure

exposure

grain growth

led

cell

cell

columnar grains

texture


Input: Increasing powder layer thickness effectively promoted the columnar-to-equiaxed grain transition (CET), leading to a greatly reduced texture and a hybrid microstructure which consists of small and chunky equiaxed grains together with a small number of large columnar grains.

powder

layer thickness

grain

microstructure

equiaxed grains

texture

columnar grains


Input: Athermal ω precipitates were observed in all the as-fabricated samples.

precipitates

samples


Input: In the samples made with high energy densities, α laths which tend to constitute a grid-like structure were observed.

samples

structure

energy densities


Input: The samples with the finest columnar grains show both high strengths and good ductility thanks to full plastic deformation through both slipping and twinning.

samples

twinning

columnar grains

strengths

ductility

plastic deformation


Input: The samples with the hybrid grain structure, however, exhibits a highly limited or no ductility due to intergranular fracturing.

samples

grain structure

ductility


Input: The α-containing samples which also have coarse grains all failed in a cleavage fracture mode and exhibited almost no ductility.

samples

grains

fracture

ductility


Input: Transmission electron microscopy study reveals that the α-demarcated grid structure tended to confine plastic deformation within the β matrix and suppress the macroscopic plastic deformation throughout the samples.

Transmission electron microscopy

structure

macroscopic

deformation

samples

plastic deformation


Input: 3-D printing shows great potential in laboratories for making customized labware and reaction vessels.

laboratories


Input: In addition, affordable fused filament fabrication (FFF) -based 3-D printing has successfully produced high-quality and affordable scientific equipment, focusing on tools without strict chemical compatibility limitations.

fused filament fabrication

FFF

equipment

tools


Input: As the additives and colorants used in 3-D printing filaments are proprietary, their compatibility with common chemicals is unknown, which has prevented their widespread use in laboratory chemical processing.

As

additives

colorants

filaments

laboratory


Input: The results provide data on materials unavailable in the literature and the chemical properties of 3-D printable plastics that were, are in line with literature.

data

materials

properties

plastics


Input: Overall, many 3-D printable plastics are compatible with concentrated solutions.

plastics


Input: Polypropylene emerged as a promising 3-D printable material for semiconductor processing due to its tolerance of strongly oxidizing acids, such as nitric and sulfuric acids.

Polypropylene

as

material

semiconductor

as

tolerance


Input: In addition, 3-D printed custom tools were demonstrated for a range of wet processing applications.

tools

range


Input: The results show that 3-D printed plastics are potential materials for bespoke chemically resistant labware at less than 10% of the cost of such purchased tools.

materials

plastics

tools


Input: However, further studies are required to ascertain if such materials are fully compatible with clean room processing.

materials

clean room


Input: Large pulsed electron beam irradiation was proposed as the new post-treatment of the selective laser melting process.

electron beam

as

post-treatment

selective laser melting process


Input: LPEB irradiation can remove the partially melted particles and fill the cracks and void on the SLM-MS.

irradiation

melted

void


Input: There is the significant reduction of the surface roughness and the bcc α-martensite phase on the SLM-MS.

reduction

bcc

phase

surface roughness


Input: Corrosion testing revealed that there is a moderate improvement in corrosion resistance after LPEB irradiation.

Corrosion

corrosion resistance

irradiation


Input: The present work aimed to decrease the surface roughness of maraging steel (MS) by selective laser melting (SLM) using large pulsed electron-beam (LPEB) irradiation as a post-treatment.

surface roughness

maraging steel

as

selective laser melting

SLM

irradiation

post-treatment


Input: The MS samples were fabricated using different combinations of laser power, scanning speed, hatch distance, and build angle.

samples

fabricated

laser power

scanning speed

hatch distance

build


Input: The morphological features, surface roughness, phase content, and corrosion resistance of the MS samples in their as-fabricated (ASF) state were compared after LPEB irradiation.

surface roughness

phase

corrosion resistance

samples

irradiation


Input: The ASF SLM-MS samples exhibit the presence of partially melted particles that spread over the entire surface and many cracks in both the longitudinal and transverse directions.

samples

melted

spread

surface


Input: Post-treatment by LPEB irradiation removed the partially melted particles, while reflow of the molten mass filled the cracks and voids and facilitated the formation of a uniform surface with a bright metallic finish.

Post-treatment

irradiation

melted

voids

surface

metallic


Input: Body-centered cubic α-martensite was the predominant phase for the ASF SLM-MS samples, along with a small fraction face-centered cubic γ-austenite phase.

phase

samples

fraction

phase


Input: After LPEB irradiation, the martensite was reverted to the austenite phase.

irradiation

martensite

austenite phase


Input: The corrosion resistance of the LPEB-irradiated samples was moderately better than that of the ASF SLM-MS samples.

corrosion resistance

samples

samples


Input: The uniform surface morphology, removal of partially melted particles, absence of pores and cracks, decrease in Sa, and moderate improvement in corrosion resistance suggests that LPEB irradiation can be used as a post-treatment for SLM-MS samples.

surface morphology

melted

corrosion resistance

samples

pores

irradiation

post-treatment

be

as


Input: The laser powder bed fusion (LPBF) process produces complex microstructures and specific defects.

laser powder bed fusion

LPBF

process

defects

microstructures


Input: To build structural components with an acceptable mechanical integrity, optimization of the processing parameters is required.

build

components

mechanical integrity

optimization

parameters


Input: In addition, the evolution of defects under service conditions should be investigated.

evolution

defects

be


Input: In this study, the nickel-based alloy 718 was studied in the as-built metallurgical state.

nickel-based alloy

metallurgical


Input: Laser processing parameters such as the laser power, scanning speed, and hatch spacing were modified to evaluate their effects on the porosity, microstructure, and mechanical properties at high temperatures.

Laser processing

microstructure

mechanical properties

as

laser power

scanning speed

hatch spacing

temperatures

porosity


Input: The porosity and pore shape were evaluated using relative density measurements and image analysis.

porosity

pore

relative density

image analysis


Input: Moreover, the effects of the microstructure and defects on the tensile properties and damaging processes at 650 °C were investigated in air.

microstructure

defects

processes

tensile properties


Input: The results revealed that the loading direction is critical to the mechanical integrity of the alloy, due to the specific orientation of the microstructural interfaces and defects.

mechanical integrity

alloy

orientation

microstructural

defects


Input: A tensile test was conducted in vacuum at 650 °C and 2.10−4 s−1, and the results indicated that damage processes were not affected by oxidation when the experiments were carried out in air.

tensile test

damage

oxidation


Input: Microrobotic prototypes for water cleaning are produced combining stereolithography 3D printing and wet metallization.

prototypes

cleaning

stereolithography 3D printing

metallization


Input: Different metallic layers are deposited on 3D printed parts using both electroless and electrolytic deposition to impart required functionalities.

metallic

3D printed parts

electrolytic deposition


Input: In particular, by exploiting the flexibility and versatility of electrolytic codeposition, pollutants photodegradation and bacteria killing are for the first time combined on the same device by coating it with a composite nanocoating containing titania nanoparticles in a silver matrix.

flexibility

coating

composite

titania

silver

nanoparticles


Input: The microstructure of the microrobots thus obtained is fully characterized and they are successfully actuated by applying rotating magnetic fields.

microstructure

magnetic fields


Input: This paper presents the results of numerical simulations and experimental tests on AlSi10Mg samples, having thin cylindrical channels built in the horizontal direction, using selective laser melting technology.

numerical simulations

experimental

cylindrical

selective laser melting


Input: The thermal state of the samples with channels of varying diameters is investigated by employing a simplified part-scale transient model that takes into consideration the overmelting effects through the change of the materials properties related with phase transition effects in the melted area of the sample.

samples

transient model

materials

phase

melted

sample

area


Input: Comparison of simulation results and computing tomography of experimental samples reveal that the final cross section geometry of thin channels can be predicted and evaluated by the proposed model.

simulation

experimental

cross section

model

be


Input: Namely, it is found that the unsupported down-skin area of the channels is processed with formation of protrusions due to presence of the low conductive powder bed under the melted metal layer.

area

layer

processed

melted

powder bed


Input: This powder area overheated during laser action and melted together with desirable solid region of the model.

powder

area

laser

melted

model


Input: Overmelting effects lead to the total closing of the channels with diameter less than 200 μm, partial closing of the channels of diameters 0.2-1 mm, and distortion of the cross section of larger channels.

lead

diameter

distortion

cross section

mm


Input: Possible approaches of adjusting the geometry of a channel are studied, considering the teardrop and enlarged shapes of the cross sections, which could help obtain a predefined cylindrical shape of the channels.

geometry

cross sections

cylindrical

channel


Input: A quasi-2D model of Micro-Selective Laser Melting (μ-SLM) process using molecular dynamics is developed to investigate the localized melting and solidification of a randomly-distributed Aluminum nano-powder bed.

model

process

solidification

Laser

melting

Aluminum

bed


Input: One of the biggest challenges in modeling the μ-SLM process is the computational treatment of the formation and growth of crystal nuclei in the meltpool.

modeling

process

nuclei

meltpool


Input: The present work overcomes this challenge using molecular dynamics simulation because of its capability to explicitly model the nucleation and growth of grains inside the meltpool.

simulation

model

nucleation

grains

meltpool


Input: The localized heating and rapid solidification of meltpool is simulated by the direct control of the temperature in the meltpool both spatially and temporally.

heating

rapid solidification

meltpool

meltpool

temperature


Input: The rapid solidification in the meltpool reveals the cooling rate dependent homogeneous nucleation of equiaxed grains at the center of the meltpool.

rapid solidification

meltpool

meltpool

cooling rate

homogeneous nucleation

equiaxed grains


Input: Additionally, the epitaxial grain growth from the adjacent laser tracks, previous layers, and partially melted nano-powders into the solidifying meltpool is observed along the highest heat flow directions.

epitaxial

laser

melted

heat

meltpool


Input: The growth of the long columnar grains into the top layer is inhibited if the penetration depth during the remelting of a previous layer is less than the depth of the equiaxed grains.

columnar grains

layer

penetration depth

layer

equiaxed grains


Input: Long columnar grains that spread across three layers, equiaxed grains, nano-pores, twin boundaries, and stacking faults are observed in the final solidified nanostructure obtained after ten passes of the laser beam on three layers of Aluminum nano-powder particles.

columnar grains

spread

equiaxed grains

laser beam

particles

boundaries

Aluminum


Input: Hot isostatic pressing (HIP) of the final solidified nanostructure is employed to eliminate the nano-pores, which act as sources of crack initiation during tensile loading.

Hot isostatic pressing

HIP

as

tensile


Input: This work examines the use of dual-material fused filament fabrication for 3D printing electronic components and circuits with conductive thermoplastic filaments.

dual-material

filament

thermoplastic filaments

fabrication

3D printing

components


Input: The resistivity of traces printed from conductive thermoplastic filaments made with carbon-black, graphene, and copper as conductive fillers was found to be 12, 0.78, and 0.014 Ω cm, respectively, enabling the creation of resistors with values spanning 3 orders of magnitude.

resistivity

thermoplastic filaments

graphene

copper

as

be

resistors

magnitude


Input: The carbon black and graphene filaments were brittle and fractured easily, but the copper-based filament could be bent at least 500 times with little change in its resistance.

carbon black

graphene filaments

filament

be

brittle

resistance


Input: Impedance measurements made on the thermoplastic filaments demonstrate that the copper-based filament had an impedance similar to a copper PCB trace at frequencies greater than 1 MHz.

Impedance measurements

thermoplastic filaments

filament

copper


Input: Dual material 3D printing was used to fabricate a variety of inductors and capacitors with properties that could be predictably tuned by modifying either the geometry of the components, or the materials used to fabricate the components.

material

be

3D printing

fabricate

fabricate

capacitors

properties

geometry

materials

components

components


Input: These resistors, capacitors, and inductors were combined to create a fully 3D printed high-pass filter with properties comparable to its conventional counterparts.

resistors

capacitors

filter

3D printed

properties


Input: The relatively low impedance of the copper-based filament enabled its use for 3D printing of a receiver coil for wireless power transfer.

filament

3D printing

power


Input: We also demonstrate the ability to embed and connect surface mounted components in 3D printed objects with a low-cost ($1000 in parts), open source dual-material 3D printer.

surface

dual-material

components

3D printer

3D printed

source


Input: This work thus demonstrates the potential for FFF 3D printing to create complex, three-dimensional circuits composed of either embedded or fully-printed electronic components.

FFF 3D printing

three-dimensional

components


Input: The aim of the present study is to utilize fractographic methods employing scanning electron microscope (SEM) images to investigate the effects of build direction and orientation on the mechanical response and failure mechanism for Acrylonitrile–Butadiene–Styrene (ABS) specimens fabricated by fused deposited modeling (FDM).

scanning electron microscope

SEM

images

orientation

mechanical response

fabricated

fused

build direction

failure mechanism

ABS

modeling

FDM


Input: The material characterized here is ABS-M30 manufactured by Stratasys, Inc. Measurements of tensile strength, elongation-at-break and tensile modulus measurements along with the failure surfaces were characterized on a range of specimens at different build direction and raster orientation: ±45°, 0°, 0/90°, and 90°.

material

manufactured

failure

Stratasys

tensile strength

tensile

range

build direction

raster orientation


Input: The analysis of mechanical testing of the tensile specimens until failure will contribute to advances in creating stronger and more robust structure for various applications.

mechanical testing

tensile specimens

failure

structure


Input: Parameters, such as build direction and raster orientation, can be interdependent and exhibit varying effects on the properties of the ABS specimens.

Parameters

properties

as

be

ABS

raster orientation


Input: The ABS-M30 specimens were found to exhibit anisotropy in the mechanical response when exposed to axial tensile loading.

anisotropy

tensile

mechanical response


Input: The stress-strain data was characterized by a monotonic increase with an abrupt failure signifying brittle fracture.

data

failure

brittle fracture


Input: In certain combinations of build direction and raster orientation tensile failure was preceded by slight softening.

build direction

raster orientation

failure


Input: The tensile strength and modulus, and elongation-at-break were found to be highly dependent upon the raster orientation and build direction.

tensile strength

be

raster orientation

build direction


Input: The relationship between the mechanical properties and failure was established by fractographic analysis.

mechanical properties

failure

fractographic analysis


Input: The fractographic analysis offers insight and provides valuable experimental data for the purpose of building structures in orientations tailored to their exemplified strength.

fractographic analysis

experimental data

orientations

strength


Input: Other examples are shown where artifacts of the FDM fabrication process act to enhance tensile strength when configured properly with respect to the load.

FDM fabrication

tensile strength


Input: The study also presents a systematic scheme employing analogs to traditional fiber-reinforced polymer composites for the designation of build orientation and raster orientation parameters.

polymer composites

build orientation

raster orientation

parameters


Input: The dissolution kinetics of Laves phase has been analyzed.

Laves phase


Input: The mechanical properties of Inconel 718 are closely related to the morphology and size of the Laves phase, which must be quantitatively controlled to change the effect of the Laves phase from deleterious to beneficial.

mechanical properties

morphology

Laves phase

Laves phase

Inconel 718

be


Input: In this study, post-heat treatment was used to regulate the morphology and size of the Laves phase in Inconel 718 fabricated using laser directed energy deposition, and the dissolution behavior of the Laves phase during solution heat treatment was investigated.

morphology

Laves phase

fabricated

Laves phase

Inconel 718

laser directed energy deposition

solution heat treatment


Input: The results indicated that the sharp corners and grooves of the Laves phase preferentially dissolved, causing the morphology of the Laves phase to change from a long-striped to granular shape during dissolution.

Laves phase

morphology

Laves phase


Input: The dissolution kinetics of the Laves phase were also investigated using the Johnson–Mehl–Avrami–Kolmogorov and Singh–Flemings models.

Laves phase


Input: The initial stage of dissolution was controlled by both the long-range diffusion of Nb and the interfacial reaction.

diffusion

Nb


Input: Directed Energy Deposition was used to process 316 L in different atmosphere modes.

Directed Energy Deposition

process


Input: A slightly higher oxide content was detected in samples built using shielding gas.

oxide

samples

gas


Input: The mechanical properties in both conditions were extremely high.

mechanical properties


Input: Samples built in controlled atmosphere had slightly higher yield strength.

Samples

yield strength


Input: A correlation between tensile properties and oxide content is reported.

tensile properties

oxide


Input: Laser-Directed Energy Deposition was used to produce AISI 316L stainless steel samples.

Deposition

316L stainless steel


Input: The effect of the protective atmosphere on the microstructure and mechanical performance of AISI 316L deposited parts was investigated by building samples using a simple nitrogen shielding gas or using a nitrogen-filled build chamber.

microstructure

samples

gas

mechanical

simple

nitrogen

build chamber


Input: The effect of the different processing conditions on the microstructure was evaluated by X-ray analysis, optical and scanning electron microscopy.

microstructure

X-ray analysis

optical

scanning electron microscopy


Input: Only slight differences in the cellular dendrites morphology of samples built under different protective atmosphere conditions were observed.

dendrites

samples


Input: However, the presence of oxides was monitored too: the oxides composition and area fraction were analysed and compared by image analyses, and it was demonstrated that the protective atmosphere mainly affects the oxides dimensions.

oxides

oxides

oxides

composition

image analyses

area

dimensions


Input: The effect of the oxides and nitrogen pick-up on the mechanical performance of the samples was evaluated by tensile tests.

oxides

nitrogen

mechanical

samples

tensile tests


Input: The results revealed that the nitrogen-filled build chamber allowed the achievement of slightly higher tensile strength and elongation with respect to the other processing conditions as a consequence of the reduced size of the oxide inclusions.

build chamber

tensile strength

elongation

as

oxide inclusions


Input: Currently, the laser powder bed fusion (L-PBF) process can not offer a reproducible and predefined quality of the processed parts.

laser powder bed fusion

L-PBF

process

quality

processed


Input: Recent research on process monitoring focuses strongly on integrated optical measurement technology.

research

process monitoring

optical measurement


Input: Besides optical sensors, acoustic sensors also seem promising.

optical

sensors


Input: Previous studies have shown the potential of analyzing structure-borne and air-borne acoustic emissions in laser welding.

acoustic emissions

laser welding


Input: Only a few works evaluate the potential that lies in the L-PBF process.This work shows how the approach to structure-borne acoustic process monitoring can be elaborated by correlating acoustic signals to statistical values indicating part quality.

L-PBF

process monitoring

quality

be


Input: Density measurements according to Archimedes’ principle are used to label the layer-based acoustic data and to measure the quality.

Density measurements

data

quality


Input: The data set is then treated as a classification problem while investigating the applicability of existing artificial neural network algorithms, such as the TensorFlow in the Python language, to match acoustic data with density measurements.

data

classification

algorithms

data

as

as

artificial neural network

density measurements


Input: Heat treatment of Scandium and Zirconium modified AlMg alloys processed by Selective Laser Melting leads to precipitation of coherent Al3Sc particles.

Heat treatment

Selective Laser Melting

Zirconium

alloys

precipitation

particles


Input: The number density of coherent Al3Sc particles in heat treated condition reaches 5.2 × 1023 m−3.

density

particles

heat


Input: Coherently precipitated Al3Sc particles are < 5 nm in diameter.

particles

diameter


Input: Grain boundary particles stabilize the microstructure against grain growth during heat treatment.

Grain boundary

microstructure

grain growth

heat treatment


Input: Sc- Zr-modified Al-Mg alloy, processed by selective laser melting, offers excellent properties in the as processed condition, due to the formation of a desirable microstructure.

Al-Mg alloy

as

processed

properties

microstructure

selective laser melting


Input: As in conventional processing, such alloys are age hardenable, thereby precipitating a high fraction of finely dispersed coherent Al3 (Scx Zr1-x) intermetallics, which serve for the improvement of the mechanical strength.

As

alloys

intermetallics

fraction

mechanical strength


Input: Electron backscatter diffraction measurements and transmission electron microscopy were used to determine the effects of heat treatment and HIP on the microstructures of SLM processed specimens.

Electron backscatter diffraction

transmission electron microscopy

heat treatment

HIP

SLM

microstructures

processed


Input: In addition, the chemistry and number density of Al3Sc particles was analysed by atom probe tomography.

chemistry

particles

density

atom probe tomography


Input: The results show that the bi-modal grain size distribution observed in the as-processed condition can be maintained even after a heat treatment, due to a high density of intragranular Al3 (ScxZr1-x) precipitates, and various other particles pinning the grain boundaries.

grain size

density

distribution

particles

grain boundaries

be

precipitates

heat treatment


Input: A HIP post-processing can lead to grain growth in certain coarser grained areas, probably due to a local imbalance between driving and dragging forces, hence higher defect density and fewer pinning precipitates.

HIP

lead

precipitates

grain growth

forces

defect

areas


Input: Applying a heat treatment results in an increase of the density of ≤5 nm sized intragranular Al3 (Scx Zr1-x) particles by a factor of 4–6, reaching 3·1023 m−3 to 5·1023 m−3.

heat treatment

density

particles


Input: Shrinkage stress occur perpendicular to boundaries of primary columnar grains.

Shrinkage

boundaries

columnar grains


Input: This stress forms immobile dislocation networks that hinder dislocation movement.

stress

dislocation

dislocation


Input: Recrystallization during annealing at ≥1373 K eliminates the dislocation network.

Recrystallization

dislocation

annealing

K


Input: Networks of connected deformation and annealing twins block dislocation movement.

deformation

dislocation

annealing


Input: Dislocation walls were found near grain boundaries.

Dislocation

grain boundaries


Input: To widen the applications of FeCoCrNi high-entropy alloys (HEAs) fabricated via selective laser melting, their mechanical properties must be improved, and annealing plays an important role in this regard.

alloys

be

fabricated

mechanical properties

selective laser melting

annealing


Input: In this study, the microstructure, residual stress, and mechanical properties of the as-printed specimen and specimens annealed at 773–1573 K for 2 h were compared.

microstructure

mechanical properties

residual stress

K


Input: As the annealing temperature increased, the specimen structure recrystallized from all columnar grains to equiaxial grains containing numerous annealing twins.

As

annealing

recrystallized

annealing

structure

grains

columnar grains


Input: The dislocation network, which formed during the solidification process under considerable shrinkage strain, decomposed into dislocations.

dislocation

shrinkage

dislocations

solidification process


Input: The residual stress, yield strength, and hardness decreased, while the plasticity and impact toughness increased.

residual stress

yield strength

hardness

plasticity

impact


Input: During the deformation of as-printed and low-temperature-annealed specimens, the dislocation network remained unchanged and provided resistance to the dislocations moving within it, thus strengthening the specimen.

deformation

dislocation

dislocations

resistance

strengthening


Input: The tensile strength remained largely unchanged owing to the reduction in the residual stress during low-temperature annealing, as well as the formation of the twinning network and dislocation wall under large deformation upon high-temperature annealing.

tensile strength

residual stress

reduction

twinning

dislocation

deformation

annealing

annealing

as

as


Input: Meanwhile, the ductility greatly increased, thus increasing the potential for industrial application of HEAs.

ductility

industrial


Input: First-time fabrication of FCC + BCC dual-phase high-entropy alloys (DP-HEAs) by SLM.

fabrication

SLM

FCC

BCC

alloys


Input: New alloy design strategy for attaining strong, yet ductile DP-HEAs suitable for rapid solidification.

alloy

ductile

rapid solidification


Input: Deformation nano-twins, stacking faults and strain-activated B2-to-FCC phase transition are discovered in BCC phase.

Deformation

phase

BCC


Input: The deformation mechanisms of the FCC and B2 phases are uncovered.

deformation

FCC


Input: Preparing dual-phase high-entropy alloys (DP-HEAs) by selective laser melting (SLM) has never been achieved owing to high crack susceptibility induced by rapid solidification.

alloys

selective laser melting

SLM

rapid solidification

susceptibility


Input: Here we design and fabricate new face-centered cubic (FCC) and body-centered cubic (BCC) DP-HEAs based on BCC AlCrCuFeNi HEA using SLM.

design

fabricate

SLM

FCC

BCC

BCC


Input: Results show that the addition of Ni facilitates the columnar-to-near-equiaxed transition and improves the formability of the as-built AlCrCuFeNix (2.0 ≤ x ≤ 3.0) HEAs.

Ni

transition

formability


Input: Especially, the as-built AlCrCuFeNi3.0 HEA exhibits modulated nano-sized lamellar or cellular dual-phase structures and possesses the best combination of ultimate tensile strength (∼ 957 MPa) and ductility (∼ 14.3%).

lamellar

MPa

ultimate tensile strength

ductility


Input: Post-deformation research reveals that the FCC phase is deformed through planar dislocation slip with {111} < 110 > slip systems, and stacking faults (SFs).

research

FCC

dislocation

deformed


Input: Strain-activated B2-to-FCC phase transition occurs in the B2 phase.

phase

phase


Input: The uncovered synergy of various deformation modes and the underlying back stress strengthening induced by heterogeneous microstructures contribute to the high ultimate tensile strength and good ductility of the as-built AlCrCuFeNi3.0 HEA.

deformation

heterogeneous

stress

ultimate tensile strength

ductility

strengthening


Input: 3D printing of flexible conductive nanocomposites were investigated.

3D printing


Input: Conductivity was found largely independent of process temperatures.

Conductivity

process


Input: Anisotropy in conductivity was observed up to an order of magnitude.

Anisotropy

conductivity

magnitude


Input: Soft actuators with built-in touch sensors was successfully printed.

actuators

sensors


Input: Soft actuators with built-in piezoresistive sensing was demonstrated.

actuators

sensing


Input: With applications in flexible electronics and soft robotics, the ability to fabricate elastic functional materials with complex geometries has become highly desirable.

electronics

materials

complex geometries

soft robotics

fabricate

elastic


Input: In this work, flexible thermoplastic polyurethane/multiwalled carbon nanotube (TPU-MWCNT) composites were printed using multi-material fused filament fabrication (FFF) to study their feasibility towards built-in sensing capabilities in soft robotics.

thermoplastic

carbon nanotube

composites

multi-material

feasibility

fused filament fabrication

FFF

sensing

soft robotics


Input: The microstructure, electrical conductivity, capacitive sensing, and piezoresistive sensing of the printed samples were investigated.

microstructure

samples

electrical conductivity

sensing

sensing


Input: MWCNT content, print orientation, and layer height was found to be the most influential parameters on the electrical properties while the nozzle and bed temperatures showed insignificant impacts.

print

orientation

parameters

electrical properties

layer height

be

nozzle

bed


Input: Overall, the in-line and through-line conductivities were one order of magnitude higher than the through-layer conductivity.

magnitude

conductivity


Input: A soft pneumatic actuator was then designed and printed out of TPU-MWCNT using the optimized process conditions.

actuator

designed

process


Input: The built-in capacitive and piezoresistive sensing capabilities of the printed actuators were successfully demonstrated upon gripping contact and actuation at three different pressure levels.

sensing

contact

actuators

pressure


Input: This work unveils the potential of integrating a variety of feedback sensors in robotic actuators through FFF process.

feedback

actuators

FFF


Input: In this study, commercially pure titanium (CP-Ti) parts were successfully fabricated by selective laser melting (SLM) using cost-effective hydride-dehydride (HDH) Ti powders for the first time modified by jet milling.

titanium

Ti powders

fabricated

selective laser melting

SLM

milling


Input: Jet milling effectively improves the particle-shape sphericity, suppresses the impurity pick-up, and produces localized plastic deformation.

milling

impurity

plastic deformation


Input: The oxide layer in the powder surface is determined with the thickness of ∼8 nm and TiO being the predominant phase before and after jet milling.

oxide

powder

layer

phase

milling


Input: The SLM-made (SLMed) CP-Ti achieves dominant martensitic α’ phase with the fracture tensile strength up to 731.5 ± 5.7 MPa and elongation of 20.5 ± 1.1%, comparable with those using expensive atomized powders.

SLMed

phase

fracture

MPa

strength

elongation

atomized


Input: Contrary to the conventional metallurgical mechanism for Ti which suffers the cost-performance dilemma, this work presents SLMed CP-Ti with excellent synergy of strength and ductility while using the cost-affordable HDH Ti powders.

metallurgical

mechanism

Ti

Ti powders

SLMed

strength

ductility


Input: In this work the tensile behaviour of selective laser melted (SLMed) aluminium alloy A357 in the as-fabricated and heat-treated states is explained using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and transmission electron backscatter diffraction (t-EBSD).

tensile

selective laser melted

SLMed

heat-treated

aluminium alloy

scanning electron microscopy

SEM

electron backscatter diffraction

EBSD

transmission electron microscopy

TEM

transmission

electron backscatter diffraction


Input: The as-built sample has an ultrafine microstructure, with high residual stresses and non-equilibrium solid solute concentration of Si in the supersaturated Al matrix.

sample

microstructure

residual stresses

Si

Al


Input: Consequently, the tensile properties of the SLMed Al alloy A357 are comparable or better than traditional cast counterparts.

tensile properties

SLMed

cast

Al alloy


Input: The Al grains in the SLMed alloy consist of sub-micron sized Al cells, and both high angle and low angle boundaries are initially occupied by eutectic nano-sized Si particles, which are beneficial for strength but detrimental for ductility.

Al

alloy

Al

Si

SLMed

sub-micron

boundaries

eutectic

particles

strength

ductility


Input: With subsequent solution heat treatment, the Si particles on the low angle cell boundaries (LACBs) dissolve while those at the high angle grain boundaries (HAGBs) coarsen.

solution heat treatment

Si

particles

grain boundaries

cell

boundaries


Input: Simultaneously internal stresses decrease, as does solute content in the matrix.

internal stresses

as


Input: The evolution of these microstructural features explains the improved tensile ductility (at its maximum > 23%) and reduced tensile strength for the heat treated SLMed aluminium alloy A357 samples.

evolution

microstructural

heat

samples

tensile ductility

tensile strength

SLMed

aluminium alloy


Input: Correlations between microstructures and corrosion resistances of SLMed Inconel 718 alloy are studied.

microstructures

Inconel 718 alloy

corrosion resistances

SLMed


Input: Platelet-shape δ phases are discovered after solution annealing treatment.

solution annealing treatment


Input: Corrosion micro-batteries cause the formation of pits or cracks at secondary phase boundaries.

Corrosion

phase boundaries


Input: Corrosion mechanism of SLMed Inconel 718 alloy is revealed.

Corrosion

SLMed

Inconel 718 alloy


Input: The microstructures and corrosion resistances of Inconel 718 alloy prepared by selective laser melting (SLM), SLM following various heat treatments, and conventional rolling are studied.

microstructures

Inconel 718 alloy

corrosion resistances

selective laser melting

SLM

SLM

heat treatments

rolling


Input: Results show that only Nb element is enriched in interdendritic regions while Fe element is abundant in dendritic trunks for the as-built Inconel 718 alloy.

Nb

element

Fe

element

Inconel 718 alloy


Input: After solution annealing treatment, incomplete recrystallization is observed and distortion energy is released.

solution annealing treatment

recrystallization

distortion


Input: Increasing the solution annealing temperature from 980 °C to 1020 °C (ST1∼ST3), the morphologies of δ phases turn from needle-like into short platelet shape, which reduces the anodic current density and improves the corrosion resistance compared to other heat-treated samples in 3.5 wt% NaCl solution.

solution

morphologies

corrosion resistance

annealing

heat-treated

density

NaCl


Input: Corrosion morphology observation shows that obvious cracking of surface passive film occurs for the SLM, solution annealing plus double aging (SA) and rolled samples, while corrosion pits and micro-cracks appear at the δ phase boundaries of solution-annealed (ST1∼ST3) samples.

Corrosion

cracking

surface

solution

samples

corrosion

micro-cracks

phase boundaries

samples

SLM

annealing


Input: The surface passive film is smooth for the rolled sample.

surface

sample


Input: The corrosion resistance of samples obtained by different processes follows in the order of rolled > ST3 > ST2 > ST1 > SA > SLM.

corrosion resistance

samples

processes

SLM


Input: The high interface energy and lattice misfit may provide driving forces for the preferential dissolution of γ matrix rather than second phases.

interface

lattice

forces


Input: The inferior corrosion resistance of the as-built Inconel 718 alloy can be significantly improved through solution annealing treatment at 1020 °C.

corrosion resistance

Inconel 718 alloy

be

solution annealing treatment


Input: The increase of molecular weight of partcake powder could be traced back to a linear chain growth/post condensation reaction with GPC analysis.

weight

powder

be


Input: The influence of build time in selective laser sintering on molecular changes of polyamide 12 powder is more significant than the effect of build temperature.

build time

build

selective laser sintering

polyamide 12


Input: With increasing molecular weight, the chain mobility is reduced and the crystallization temperature shifts to lower temperatures.

weight

temperatures

crystallization


Input: This broadens the processing window, but higher molecular weights go along with a higher viscosity, which is not favorable for SLS process.

go

viscosity

SLS process


Input: The material aging in selective laser sintering SLS of polyamide 12 is one challenge, which has to be overcome for implementation of this technique in serial production.

material aging

selective laser sintering

production

polyamide 12

be


Input: High temperatures and along going processing times lead to chemical and physical aging effects of the supporting partcake material.

temperatures

lead

material


Input: The investigations in this study aims at the influence of processing time and temperature on molecular changes and thermal properties of polyamide 12 partcake material in selective laser sintering.

temperature

thermal properties

polyamide 12

material

selective laser sintering


Input: The focus of the investigations lays on the global heat exposure of the of the bulk material und thus on global material changes.

heat exposure

material

material


Input: Gel permeation chromatography analysis was used to determine the molecular weight distribution and changes of polymer structure.

Gel

polymer

weight

distribution


Input: With increasing build time and build chamber temperature the average molecular weight is rising, whereby the influence of build time is more significant.

build time

build chamber

weight

build time

average


Input: The rise of chain length leads to a reduction of crystallization temperature, which was detected by DSC.

reduction

crystallization

DSC


Input: This work investigated the superelastic response of the low-modulus porous β type Ti-35Nb-2Ta-3Zr scaffolds with different pore dimensions fabricated by laser powder bed fusion.

porous

scaffolds

pore dimensions

fabricated

laser powder bed fusion


Input: The superelastic behavior was enhanced with increasing the pore size and stress-induced phase transformation, which correspondingly led to stress-induced α'' [110] -type I twin martensitic transformation and ω formation adjacent to β matrix/twins.

pore size

phase

led


Input: The resultant interstitial compound phase structure facilitated the β → α'' and β → ω transition, which was triggered by interfacial stress/strain concentration and high-density dislocations.

phase

transition

dislocations


Input: Substantial high-angle grain boundaries (HAGBs) accumulated high-intensity Schimd factor and crystallographic texture after being deformed.

grain boundaries

texture

deformed


Input: Moreover, a lower Young’ s modulus was obtained when the pore size and stress increased.

s

pore size

stress


Input: A vision-based inspection system based on three digital cameras is proposed for measuring the cladding height in the Direct Energy Deposition (DED) process.

inspection

cladding

Direct Energy Deposition

DED

process


Input: To improve the accuracy of the cladding height measurements, an image processing technique is applied to remove the undesirable zone from the binary image.

accuracy

cladding

image

binary


Input: Furthermore, since the unit length in the captured images is different to that in the world coordinate framework, a calibration bar method is designed to transform the pixel value to the real size.

images

calibration

coordinate

designed


Input: An image-processing technique is then employed to isolate the laser nozzle and melt pool in the captured images.

laser

melt pool

images


Input: Finally, the cladding height is estimated based on the distance between the tip of the laser nozzle and the centroid of the melt pool.

cladding

laser

melt pool


Input: The validity of the proposed approach is demonstrated by comparing the inspection results for the cladding height of a horseshoe component with the measurements obtained using a 3-D scanner.

inspection

cladding

component


Input: The maximum estimation error is found to be just 4.2% Overall, the results confirm that the proposed trinocular vision-based system provides a rapid, convenient and accurate means of determining the cladding height in the DED process.

error

be

accurate

cladding

DED


Input: The aim of this study is to promote the magnetic shielding characteristics of laser powder bed fusion (LPBF) processed NiFeMo alloy.

laser powder bed fusion

LPBF

processed

alloy


Input: This was achieved via controlling the crystallographic texture of the builds to increase the grain population along the easy axis of magnetisation, as well as the use of post-process hydrogen heat treatment (HT) and hot isostatic pressing (HIP) processes.

texture

builds

grain

post-process

processes

as

as

heat treatment

hot isostatic pressing

HIP


Input: The as-fabricated microstructure typically demonstrates weak magnetic properties due to the alignment of the crystallographic orientation/spin order along the [100] hard axis of magnetisation, which is parallel to the build direction since it is also the preferred growth direction during solidification in cubic materials.

microstructure

properties

solidification

materials

build direction


Input: The improved ferromagnetism following HIP + HT was due to several combined effects, including stress relief, consolidation of gas pores, recrystallisation, and grain growth.

ferromagnetism

stress

HIP

consolidation

gas

grain growth


Input: The post-processing sequence (HT + HIP vs. HIP + HT) appeared to affect the resulting magnetic characteristics.

post-processing

HIP

HIP


Input: Finally, the tensile properties for the builds were characterised to ensure that both functional and mechanical behaviours would achieve the required performance.

tensile properties

builds

mechanical behaviours

performance


Input: Usually the process gas flow rates and the process gas types are not regarded as the primary process parameters of the laser cladding process.

process gas

process gas

process parameters

flow rates

as

laser cladding


Input: Herein it is shown, how the melt pool surface oxidation can be significantly reduced by the change of the carrier gas type, by a reduced carrier gas flow rate and by minor changes in the powder nozzle design.

melt pool

be

powder

oxidation

gas

gas flow rate

nozzle

design


Input: A simulation model for the gas flow and the powder particle flow between the powder nozzle and the melt pool surface has been developed, which reveals the volume percentage of different gas types and so the quality of the shield gas atmosphere.

simulation

model

gas

volume

gas

quality

gas

powder particle

powder

melt pool

nozzle


Input: Additionally, the powder particle distribution and the attenuation of the laser beam by the powder particles can be simulated.

powder particle

powder particles

be

distribution

laser beam


Input: The simulation results are confirmed by experimental measurements of the powder particle density distribution in the working plane, by measurements of the oxygen volume percentage at the workpiece surface, by high-speed camera images of the melt pool surface and by absorptivity measurements, which show the effect of oxidation on the process.

simulation

experimental

workpiece

surface

process

powder particle

oxygen

melt pool

density distribution

camera

oxidation


Input: TiB precipitates were significantly refined in the EB-PBF-built Ti-6242S-1.0B alloy compared with forged alloys.

precipitates

alloy

alloys


Input: Finer oxides contributed to the formation of more compact oxidation layers in the EB-PBF-built alloy than as-forged alloy.

oxides

alloy

alloy

compact


Input: Evaporation of B2O3 from coarse TiB particles destabilized the oxidation layer in the as-forged alloy.

Evaporation

particles

alloy

oxidation

layer


Input: Evaporation of B2O3 from fine TiB particles did not destabilize the oxidation layer in the EB-PBF-built alloy.

Evaporation

particles

alloy

oxidation

layer


Input: EB-PBF-built Ti-6242S-1.0B alloy was more resistant to oxidation than the as-forged alloy.

alloy

alloy

oxidation


Input: Refined TiB precipitates significantly enhance the oxidation resistance of Ti-6Al-2Sn-4Zr-2Mo-0.1Si-1.0B alloy fabricated by electron beam powder bed fusion (EB-PBF).

precipitates

alloy

oxidation resistance

electron beam

bed fusion


Input: Refined TiB precipitates in the EB-PBF-built alloy enable finer oxide formation than the larger precipitates in the forged alloy, and the resulting oxidation layers are more compact.

precipitates

alloy

oxide

precipitates

alloy

oxidation

compact


Input: Evaporation of scattered B2O3 generated by the refined TiB precipitates in the EB-PBF-built alloy do not significantly accelerate detachment of the oxidation layer from the substrate.

Evaporation

precipitates

alloy

substrate

oxidation

layer


Input: However, collective evaporation of B2O3 generated by larger TiB precipitates in the forged alloy accelerate detachment.

evaporation

precipitates

alloy


Input: The oxidation layer on the EB-PBF-fabricated alloy was more stable, preventing further oxidation and improving oxidation resistance.

oxidation

oxidation

layer

alloy

oxidation resistance


Input: We report on the development of a miniaturized device for operando X-ray diffraction during laser 3D printing.

X-ray diffraction

laser

3D printing


Input: We describe the design considerations, details on the setup and the implementation at two different beamlines of the Swiss Light Source.

design considerations

Light Source


Input: Its capabilities are demonstrated by ex situ printing of complex shapes and operando X-ray diffraction experiments using Ti-6Al-4V powder.

complex shapes

X-ray diffraction

Ti-6Al-4V powder


Input: It is shown that the beamline characteristics have an important influence on the X-ray footprints of the microstructural evolution during 3D printing.

X-ray

microstructural evolution

3D printing


Input: From the intensity of the diffraction peaks, the evolution of the different phases can be followed during printing.

diffraction

evolution

be


Input: Furthermore, the diffuse scattering signal provides information on the precise location of the laser beam on the sample and the scanning head settling time.

laser beam

sample

scanning


Input: Some AM processes such as directed energy deposition (DED) have typical powder usage efficiencies ranging between 40 and 80%.

AM processes

DED

as

powder

deposition


Input: Since, for a given alloy, powder cost is proportional to its purity, choosing a less expensive powder or reusing powders is interesting for economical and environmental reasons.

alloy

powder

powder

powders


Input: The work summarized below studied the effect of oxygen content in Ti6Al4V powders on mechanical properties of AM parts fabricated by DED.

oxygen

Ti6Al4V powders

mechanical properties

AM parts

DED


Input: Three different powders with increasing oxygen content were used to produce specimens and characterize its effect on microstructure and tensile properties before and after heat treatment.

powders

oxygen

microstructure

tensile properties

heat treatment


Input: Only coarsening of the particle size distribution and the presence of fragmented particles was observed for the recycled powder.

particle size distribution

particles

recycled

powder


Input: Comparing the chemistry of parts vs that of powder feedstock it was determined that for all the tests, the Al content was slightly lower in the parts and that no significant loss of vanadium was noted when printing with new (fresh) powders.

chemistry

powder feedstock

Al

vanadium

powders


Input: On the other hand, V loss was significant in parts made with recycled powders, although still leaving them within acceptable chemistry to respect their original grade 5 classification.

V

powders

recycled

chemistry

classification


Input: The build quality of laser Powder Bed Fusion (PBF) components largely depends on printing issues such as inter-track voids and undesired microstructure.

build

laser Powder Bed Fusion

PBF

components

as

voids

microstructure


Input: In this work, a comprehensive phenomenological model was developed to compute the complex transport phenomena during laser PBF of Ti-6Al-4V.

phenomenological model

transport

laser


Input: The transient temperature and velocity fields during single-track and multi-track laser PBF were computed considering the melting and solidification of the powder feedstocks.

transient

solidification

temperature

laser

melting

powder feedstocks


Input: Critical metallurgical variables including the molten pool characteristics and thermal cycles were obtained.

metallurgical

molten pool

thermal cycles


Input: The model was validated by comparing the computed results against corresponding experimental data.

model

experimental data


Input: The formation and evolution of inter-track voids in different heat input conditions were studied.

evolution

voids

heat


Input: The first type appeared in irregular elongated shapes and was caused by the incomplete melting of the powder feedstocks.

melting

powder feedstocks


Input: Cooling rates were obtained to interpret the metallurgical conditions for the solid-state phase transformations.

Cooling rates

metallurgical

solid-state phase


Input: The novel findings from this research are helpful to the understanding of the formation and mitigation of inter-track voids, and the assessment of phase transformations during laser PBF of titanium alloys.

research

voids

phase

laser

titanium alloys


Input: The fracture toughness (K1c) and fatigue crack growth rate (FCGR) properties of selective laser melted (SLM) specimens produced from grade 5 Ti6Al4V powder metal has been investigated.

fracture

properties

fatigue crack growth rate

selective laser melted

SLM

Ti6Al4V powder metal


Input: Three specimen orientations relative to the build direction as well as two different post-build heat treatments were considered.

orientations

build direction

as

as

heat treatments


Input: Specimens and test procedures were designed in accordance with ASTM E399 and ASTM E647 standard.

designed

standard


Input: The results show that there is a strong influence of post-build processing (heat treated versus ‘as built’) as well as specimen orientation on the dynamic behaviour of SLM produced Ti6Al4V.

heat

orientation

dynamic

as

as

as

SLM


Input: The greatest improvement in properties after heat treatment was demonstrated when the fracture plane is perpendicular to the SLM build direction.

properties

fracture

heat treatment

SLM

build direction


Input: This behaviour is attributed to the higher anticipated influence of tensile residual stress for this orientation.

tensile residual stress

orientation


Input: The transformation of the initial rapidly solidified microstructure during heat treatment has a smaller beneficial effect on improving mechanical properties.

rapidly solidified

heat treatment

microstructure

mechanical properties


Input: 3D-printed PLA/Ti scaffolds with tailored porosity and pore size were fabricated via fused filament fabrication (FFF).

fused filament fabrication

FFF

scaffolds

porosity

pore size

fabricated


Input: Thermal properties of PLA/Ti filaments were changed by the addition of Ti.

Thermal properties

filaments

Ti


Input: 5–10 vol% of Ti enhanced the mechanical properties of 3D-printed PLA/Ti scaffolds.

Ti

mechanical properties

scaffolds


Input: In vitro assays showed good cell responses in PLA/Ti scaffolds.

cell

scaffolds


Input: 3D-printed PLA/Ti scaffolds have potential as bone substitutes for tissue engineering.

scaffolds

as

tissue engineering


Input: Ideal bone substitutes should ensure good integration with bone tissue and are therefore required to exhibit good mechanical stability and biocompatibility.

bone

bone

mechanical

biocompatibility


Input: Consequently, the high elastic modulus (similar to that of bone), thermoplasticity, and biocompatibility of poly (lactic acid) (PLA) make it well suited for the fabrication of such substitutes by fused filament fabrication (FFF) -based 3D printing.

elastic modulus

biocompatibility

bone

PLA

fabrication

fused filament fabrication

FFF

3D printing


Input: However, the demands of present-day applications require the mechanical and biological properties of PLA to be further improved.

mechanical

properties

PLA

be


Input: Herein, we fabricated PLA/Ti composite scaffolds by FFF-based 3D printing and used thermogravimetric analysis to confirm the homogenous dispersion of Ti particles in the PLA matrix at loadings of 5–20 vol%.

fabricated

dispersion

particles

composite

Ti

PLA

3D printing

thermogravimetric analysis


Input: Notably, the thermal stability of these composites and the crystallization temperature/crystallinity degree of PLA therein decreased with increasing Ti content, while the corresponding glass transition temperature and melting temperature concomitantly increased.

thermal stability

composites

PLA

Ti

crystallization

glass transition temperature

melting temperature


Input: The compressive and tensile strengths of PLA/Ti composites increased with Ti increasing loading until it reached 10 vol% and were within the range of real bone values, while the impact strengths of the above composites significantly exceeded that of pure PLA.

tensile strengths

composites

Ti

composites

PLA

range

bone

impact


Input: The incorporation of Ti resulted in enhanced in vitro biocompatibility, promoting the initial attachment, proliferation, and differentiation of pre-osteoblast cells, which allowed us to conclude that the prepared PLA/Ti composite scaffolds with enhanced mechanical and biological properties are promising candidates for bone tissue engineering applications.

Ti

composite

biocompatibility

cells

mechanical

engineering

properties

bone


Input: Effect of laser conditions on selectively laser melted maraging steel was studied.

laser

laser

maraging steel


Input: Volumetric energy density could not always clarify the change in relative density.

energy density

relative density


Input: Deposited energy density could clarify the change in relative density.

energy density

relative density


Input: This study provides an important insight for selectively laser melted materials.

laser

materials


Input: In this study, the effects of laser power and scan speed on the relative density, melt pool depth, and Vickers hardness of selectively laser melted (SLM) maraging steel were systematically investigated.

laser power

scan speed

melt pool depth

relative density

Vickers hardness

laser

SLM

maraging steel


Input: The change in these structural parameters and hardness could not always be clarified by the volumetric energy density, which is widely used in the SLM processes.

parameters

processes

hardness

be

energy density

SLM


Input: The deposited energy density, wherein the thermal diffusion length is used as a heat-distributed depth, can express the change in these structural parameters and the hardness with one curve.

energy density

diffusion

parameters

as

hardness


Input: To clarify the effect of the laser parameters, the deposited energy should be used instead of the volumetric energy density.

laser

be

energy density


Input: Thus, this study provides a new insight on the selection of the laser condition for SLM-fabricated materials.

laser

materials


Input: This work presents a comprehensive study on the influence of three different processing technologies (Selective Laser Melting, Hot Pressing and conventional casting) on the microstructure, mechanical and wear behavior of an austenitic 316L Stainless Steel.

technologies

microstructure

wear

Selective Laser Melting

Hot Pressing

casting

mechanical

austenitic

316L Stainless Steel


Input: A correlation between the processing technologies, the obtained microstructure and the mechanical and wear behavior was achieved.

technologies

microstructure

wear

mechanical