Input: The microstructures and high-temperature tensile properties of the rods were investigated by taking into account the effect of the BD.

microstructures

tensile properties


Input: Columnar grain structures or mixtures of columnar and equiaxed grains were obtained in the rods.

Columnar grain

equiaxed grains


Input: As a result, the crystal orientation of the rods could be controlled by appropriate choice of the CA.

As

be

CA

crystal orientation


Input: The highest strength was obtained for the < 1 1 1 > oriented rod.

strength

rod


Input: The dependence of strength on the rod orientation could be explained in terms of the anisotropies in the crystal orientation, columnar grain structure, and arrangement of the precipitate particles.

strength

crystal orientation

columnar grain

rod

orientation

particles

be

precipitate


Input: This paper presents the very first study on additive manufacturing (AM) of a high melting point near-eutectic V–9Si–5B alloy via direct energy deposition (DED).

additive manufacturing

AM

direct energy deposition

DED

melting point

alloy


Input: Tailored V–9Si–5B powder material was produced by means of a gas atomization (GA) process.

powder material

GA

gas atomization

process


Input: A novel setup for the DED experiments was developed and an overview of the production parameters for manufacturing of crack-free specimens is given.

DED

production

manufacturing

parameters


Input: The microstructural evolution of the three-phase V–9Si–5B alloy is described by means of SEM, EBSD and STEM analyses during the entire process chain, i.e.

microstructural evolution

alloy

SEM

EBSD

process chain


Input: the gas atomization of the powder material, the consolidation via DED and the heat treatment of the compacts.

gas atomization

DED

heat treatment

powder material

compacts

consolidation


Input: First mechanical tests demonstrate the high hardness and the competitive creep resistance of the AM V–9Si–5B material in comparison to other three-phase V-based alloys.

mechanical tests

hardness

creep

AM

material

alloys


Input: Metal additive manufacturing offers a tool to bring formerly unmanufacturable, geometrically complex, engineered structures into existence.

Metal additive manufacturing

tool


Input: However, considerable challenges remain in controlling the unique microstructures, defects and properties that are created through this process.

microstructures

defects

properties

process


Input: For the first time this work demonstrates how LaB6 nanoparticles can be used to control such features in Al alloys produced by Selective Laser Melting (SLM).

nanoparticles

be

Al alloys

Selective Laser Melting

SLM


Input: A novel and efficient mechanical agitation process is used to inoculate AlSi10Mg powder with LaB6 nanoparticles which resulted in a homogenous, crack-free, equiaxed, very fine-grained as built microstructures.

mechanical

agitation

nanoparticles

as

microstructures


Input: The substantial grain refinement is attributed to the good crystallographic atomic matching across the Al/LaB6 interfaces which facilitated Al nucleation on the LaB6 nanoparticles.

grain refinement

Al

nanoparticles


Input: The LaB6-inoculated AlSi10Mg exhibited near-isotropic mechanical properties with an improved plasticity compared with un modified AlSi10Mg.

mechanical properties

plasticity


Input: Selective laser melting (SLM) has become one of the most commonly utilized processes in metal additive manufacturing (AM).

Selective laser melting

SLM

metal additive manufacturing

AM

processes


Input: Despite its widespread use and capabilities, SLM parts are still being produced with excessive volumetric defects and flaws.

SLM

defects

flaws


Input: The complex dependence of defect formation on process parameters, geometry, and material properties has inhibited effective quality assurance in SLM production.

defect

process parameters

geometry

material properties

quality

SLM production


Input: Exacerbating these issues are the difficulties thus far in accurately detecting and identifying defects in-process so that parts may be qualified without destructive testing.

accurately

destructive testing

defects

be


Input: Some of the most detrimental defects produced during SLM processing are lack of fusion (LoF) defects, which are frequently found to be in excess of 100 μm in size, thus these defects are of critical importance to detect and remove.

defects

fusion

defects

defects

SLM

be


Input: In this work, we have developed and demonstrated the capabilities of a novel in situ monitoring system using full-field infrared (IR) thermography to monitor AlSi10Mg specimens during SLM production.

in situ

infrared

monitor

IR

SLM production


Input: Using layerwise relative surface temperature measurements, subsurface defects were identified via their retained thermal signature at the surface; transient thermal modeling was performed, which supported these observations.

surface

defects

surface

transient

thermal modeling


Input: Parts were characterized using ex situ scanning electron microscopy (SEM) to validate data identified defects and, critically, to estimate detection success.

scanning electron microscopy

SEM

data

defects


Input: The IR defect detection method was highly effective in identifying defects, with an 82% total success rate for LoF defects; detection success improved with increasing defect size.

IR

defect

defects

defects

defect


Input: The method was also used statistically to analyze the presence of systematic process errors during SLM production, expanding the capabilities of IR monitoring methods.

process errors

SLM production

IR


Input: This unique analysis method and simple integration for in situ IR monitoring can immediately improve non-destructive qualification methods in SLM processing.

simple

SLM

in situ


Input: Additive manufacturing has opened doors for the efficient fabrication of individually tailored and complicated functional parts.

Additive manufacturing

fabrication


Input: However, the three-dimensional (3D) printing process is vulnerable to defects generation, necessitating the need for in-situ monitoring and control technologies for quality assessment of parts.

three-dimensional

defects

in-situ

technologies

quality

printing process


Input: An in-situ monitoring system (IMS) based on optical imaging was developed in-house for implementation on the selective laser melting process.

in-situ

optical

imaging

selective laser melting process


Input: A digital single lens reflex camera, mirror and several sets of light emitting diode strip lights formed the main constituents of the IMS.

lens

camera

light emitting diode


Input: Cylindrical samples of 316 L stainless steel were printed with variations in their energy density.

Cylindrical

variations

stainless steel

energy density


Input: Features taken in optical images were extracted and evaluated via image processing.

optical

images

extracted

image


Input: Micro computed tomography (CT), which is capable of assessing the internal defects and recovering the 3D representation of a structure, was used as a validation method to correlate the features identified in the optical images.

computed tomography

optical

CT

defects

structure

validation

images

as


Input: Results have shown that features captured in-situ were correlated to defects detected by micro CT, revealing the potential of using optical images captured during printing as an indicator to the extent of defects present in selective laser melted parts.

in-situ

correlated

defects

images

defects

CT

optical

as

selective laser melted


Input: In recent years, the fabrication of aluminum alloy parts via laser powder bed fusion has been extensively considered in the biomedical, aerospace, and other industrial sectors, as it provides advantages such as the ability to manufacture complex shapes with high performance associated with lightweight design.

fabrication

laser powder bed fusion

aluminum alloy

as

as

biomedical

aerospace

industrial sectors

manufacture

performance

lightweight

complex shapes

design


Input: However, surface irregularities and sub-surface defects limit the full exploitation of such parts in fatigue-critical applications.

surface

defects


Input: Moreover, most of the commonly used metrological methods for surface characterization have proven to be unsuitable for determining important features such as undercuts and sub-surfaces pores.

surface characterization

be

as

pores


Input: Hence, a comprehensive coupled investigation of metrological methods and cross-sectional analysis were performed in this study to evaluate the effects of surface features and volumetric defects typical of additively manufactured materials.

surface

defects

additively manufactured


Input: Fatigue tests and fractographic analyses were conducted to support the finite element simulations and proposed fracture mechanics model.

Fatigue tests

fractographic analyses

support

finite element

fracture

model


Input: The results demonstrate that the standard metrological methods can not provide all of the data needed to model the fatigue behaviors of additively manufactured materials robustly.

standard

data

model

fatigue

additively manufactured


Input: Moreover, a statistical model describing the competition between volumetric defects and surface irregularities was developed and validated.

model

defects

surface


Input: Different L-PBF process parameters were used to additively manufacture AHSS.

L-PBF

additively manufacture

parameters


Input: FEM simulations quantified solidification parameters and melt pool shapes.

FEM

solidification parameters

melt pool


Input: High cooling rate parameters resulted in high GND densities and yield strength.

cooling rate

yield strength


Input: M & S scan strategy revealed a partial columnar to equiaxed transition.

M & S

transition


Input: In this work, the additive manufacturing technique of laser powder bed fusion (L-PBF) was used to build up X30Mn21 austenitic advanced high strength steel (AHSS) samples.

additive manufacturing

laser powder bed fusion

L-PBF

build

austenitic

steel

strength

samples


Input: Different L-PBF process parameters were used to understand the correlation between process, microstructure, texture, and mechanical properties.

L-PBF

parameters

process

microstructure

mechanical properties

texture


Input: The influence of build platform preheating (200 °C–800 °C), laser speed (550 mm/s-950 mm/s) and scan strategy (bidirectional continuous and Mark & Sleep (M & S)) on grain size, grain morphology, size of solidification cells, dislocation density, and texture was studied.

build platform

laser

M & S

grain size

dislocation density

grain

solidification

cells

texture


Input: Local solidification parameters in the melt pool e.g.

solidification parameters

melt pool


Input: cooling rates, temperature gradients and solidification velocities were simulated by a FEM heat flow model and correlated with the solidification microstructure.

cooling rates

temperature gradients

solidification velocities

FEM

model

correlated

solidification microstructure


Input: By using SEM/EBSD analysis and tensile testing, the mechanical properties of the AHSS were assessed by considering microstructural aspects.

tensile testing

mechanical properties

microstructural


Input: It was found that AHSS, produced with higher laser speeds and an alternative M & S scan strategy, revealed a reduced grain size and texture intensity.

laser

M & S

grain size

texture


Input: This was attributed to a partial columnar to equiaxed transition (CET), as well as a significantly increased density of geometrically necessary dislocations.

transition

dislocations

as

as

density


Input: Preheating of the build platform promoted columnar grain growth with a more pronounced texture, low dislocation densities, and reduced yield strength.

Preheating

build platform

columnar grain

dislocation densities

yield strength

texture


Input: The influence of cooling rate, temperature gradient and solidification velocity on microstructural and textural evolution is discussed based on fundamental solidification theories.

cooling rate

temperature gradient

solidification velocity

microstructural

evolution

solidification


Input: The process chain of this method starts with injection molding.

process chain

injection molding


Input: The polymer of this part is functionalized with LDS-additives which allow the part to be laser structured subsequently.

polymer

be


Input: This technique is less suitable for prototypes and small-scale productions of 3D-MIDs because of its properties.

prototypes

properties


Input: Contrary to the injection molding process, the additive manufacturing (AM), such as powder bed based manufacturing processes, e.g.

injection molding

additive manufacturing

AM

manufacturing processes

as

bed


Input: selective laser sintering (SLS), is a constantly emerging processing technology for the fabrication of prototypes and small-scale productions.

selective laser sintering

SLS

fabrication

technology

prototypes


Input: Unmodified polyamide 12 (PA 12), e.g.

polyamide 12

PA


Input: PA2200 (supplier: EOS GmbH) is most commonly used for the SLS of polymer parts.

EOS GmbH

SLS

polymer


Input: The LPKF Laser & Electronics AG in Garbsen, Germany, transferred the LDS-method to SLS-process.

Laser

Electronics


Input: A standard SLS-polymer part is coated with a special paint, that contains the necessary LDS-additives.

standard

coated


Input: Once coated and dried, these parts can be laser direct structured similar to standard 3D-MIDs.

coated

dried

be

standard


Input: In this study, the authors use copper particles in order to functionalize a standard polyamide 12 powder for laser activation and selective metallization.

copper

polyamide 12

standard

laser

metallization


Input: The study shows, that the addition of copper particles enables the laser direct structuring of polyamide 12.

copper

polyamide 12

laser


Input: SLS-demonstrators were successfully laser activated and selectively metallized.

laser


Input: Furthermore, the copper particles enhance the mechanical properties as well as the heat conductivity of polyamide 12.

copper

as

as

polyamide 12

mechanical properties

heat conductivity


Input: Lattice density and fabric are combined to predict anisotropic mechanical properties.

Lattice density

anisotropic

properties


Input: The resulting model is validated by mechanical testing in at least 10 directions.

model

mechanical testing


Input: Off-axis properties for Ti6Al4V and nylon lattices predicted to within 13 and 5.1%.

properties

lattices

nylon


Input: Predictions and mechanical data are correlated with R2 between 0.84 and 0.94.

Predictions

data

correlated

mechanical


Input: Additive manufacturing methods present opportunities for structures to have tailored mechanical anisotropy by integrating controlled lattice structures into their design.

Additive manufacturing

mechanical anisotropy

lattice structures

design


Input: The ability to predict anisotropic mechanical properties of such lattice structures would help tailor anisotropy and ensure adequate off-axis strength at an early stage in the design process.

anisotropic

anisotropy

strength

properties

design process

lattice structures


Input: A method is described for the development of a model to predict apparent modulus and strength based on structure density and fabric, taken from CAD data.

model

structure

strength

density

CAD


Input: The model utilises a tensorial form of well-founded power-law relationships for these variables and is fit to mechanical test data for properties in the principal directions of manufactured titanium stochastic lattices and nylon rhombic dodecahedron structures.

model

fit

data

properties

manufactured

stochastic lattices

mechanical test

nylon


Input: The results are validated against mechanical testing across at least 7 additional off-axis directions.

mechanical testing


Input: For stochastic structures, apparent modulus is predicted in 10 directions with a mean error of 13% and strength predicted with a mean error of 10%.

stochastic

predicted

error

predicted

error

strength


Input: For rhombic dodecahedron structures apparent modulus and strength are predicted in 15 directions with mean errors of 4.2% and 5.1% respectively.

strength

predicted

errors


Input: This model is the first to predict the anisotropic apparent modulus and strength of structures based on lattice density and fabric tensors and will be highly useful in the mechanical design of lattice structures.

model

anisotropic

strength

lattice density

design

lattice structures

be

mechanical


Input: A robotized laser/wire direct metal deposition system was utilized to fabricate 316LSi coupons.

direct metal deposition

fabricate


Input: The mechanical and microstructural properties were then characterized.

mechanical

microstructural


Input: It was found that different thermal histories caused by different inter-layer time intervals have significant impact on mechanical and microstructural properties.

impact

microstructural

mechanical


Input: The thin-walled samples with lower cooling rates showed coarser columnar grains, lower ultimate tensile strength, and lower hardness compared to the block samples.

samples

samples

cooling rates

columnar grains

ultimate tensile strength

hardness


Input: The melt pool was monitored in real-time.

melt pool


Input: An empirical correlation between the melt pool area and cooling rate was achieved that could enable control of scale of the final solidification structure by maintaining the melt pool size in real-time.

empirical

solidification

melt pool

melt pool

area

cooling rate


Input: Further, to study the anisotropic behavior, tensile samples were loaded in parallel and perpendicular directions with respect to the deposition direction.

anisotropic

tensile

samples

deposition direction


Input: The results indicated that samples in the perpendicular direction had lower UTS and elongation for both coupon types, revealing a weaker bonding at inter-layer/bead interface due to the existence of lack-of-fusion pores.

samples

bonding

interface

UTS

elongation

pores


Input: The capability to additively manufacture fully-functioning electronic circuits is a frontier in 3D-printed electronics that will afford unprecedented scalability, miniaturization, and conformability of electronic circuits.

additively manufacture


Input: In this paper, we report a novel procedure that employs three-dimensional (3D) additive manufacturing techniques to fabricate high-frequency, tapered-solenoid type inductors for RF applications capable of wide bandwidth performance.

three-dimensional

performance

additive manufacturing

fabricate


Input: The design includes a polymer support structure to reduce the parasitic capacitance between the inductor and the substrate, a tapered solid core, and conducting windings.

design

polymer

substrate

structure

inductor

core


Input: Each design component is printed using aerosol-jet (AJ) printing methods on a grounded coplanar waveguide such that the small end of the conical-shaped inductor is connected to the transmission line and the base of the inductor is connected to ground.

design

component

inductor

inductor

transmission


Input: Two types of solid-core inductors were fabricated: one with a printed polymer core and another with a non-printed iron core.

fabricated

polymer

iron

core

core


Input: Scattering parameter measurements establish that the polymer and iron-core inductors, combined with a 45°-polymer support structure, can achieve usable bandwidths up to 18 GHz and 40 GHz, respectively, with low insertion loss.

parameter

polymer

support structure


Input: 3D model and circuit model simulations were also carried out to study inductor performance in terms of self-resonance and insertion loss.

3D model

inductor

model


Input: The use of manufacturing to generate topology optimized components shows promise for designers.

manufacturing

topology

components


Input: However, designers who assume that additive manufacturing follows traditional manufacturing techniques may be misled due to the nuances in specific techniques.

additive manufacturing

traditional manufacturing

be


Input: Since commercial topology optimization software tools are neither designed to consider orientation of the parts nor large variations in properties, the goal of this research is to evaluate the limitations of an existing commercial topology optimization software (i.e.

topology optimization

designed

topology optimization

software

orientation

variations

properties

research

software


Input: Inspire®) using electron beam powder bed fusion (i.e.

electron beam

bed fusion


Input: Arcam®) to produce optimized Ti-6Al-4V alloy components.

Ti-6Al-4V alloy

components


Input: Emerging qualification tools from Oak Ridge National Laboratory including in-situ near-infrared imaging and log file data analysis were used to rationalize the final performance of components.

tools

components

Laboratory

in-situ

data

performance

imaging

file


Input: While the weight savings of each optimized part exceeded the initial criteria, the failure loads and locations proved instrumental in providing insight to additive manufacturing with topology optimization.

weight

failure

additive manufacturing

topology optimization


Input: This research has shown the need for a comprehensive understanding of correlations between geometry, additive manufacturing processing conditions, defect generation, and microstructure for characterization of complex components such as those designed by topology optimization.

research

geometry

defect

microstructure

additive manufacturing

components

as

designed

topology optimization


Input: Ni-Cu-base alloy plates have been obtained by wire arc additive manufacturing technology.

alloy

wire arc additive manufacturing

technology


Input: Dendritic structure and particle precipitation have been found to significantly depend on alloy composition, in particular Mn, Ti and C contents.

structure

particle

alloy

Mn

Ti

C


Input: Higher hardness, strength, toughness and wear resistance in one of the tested alloys were associated with precipitation of TiCN particles.

hardness

strength

toughness

wear resistance

alloys

precipitation

particles


Input: Moderate dependence of microstructural parameters and mechanical properties on deposition speed was observed within the tested speed range.

microstructural

mechanical properties

deposition

range


Input: Two Ni-Cu alloys (Monel K500 and FM 60) having various Mn, Fe, Al, Ti and C contents were deposited on a Monel K500 plate at three different speeds using wire arc additive manufacturing technique.

alloys

Monel

Mn

Fe

Al

Ti

C

Monel

wire arc additive manufacturing


Input: Microstructure characterisation, in particular a detailed study of precipitates, was carried out using optical and scanning electron microscopy.

Microstructure

precipitates

optical

scanning electron microscopy


Input: Mechanical properties were assessed using hardness, tensile and wear testing.

Mechanical properties

wear

hardness

tensile

testing


Input: For similar deposition conditions, Monel K500 has exhibited smaller secondary dendrite arm spacing and higher number density of Ti-rich particles, although the Ti concentration in FM 60 was higher.

deposition

particles

Monel

secondary dendrite

Ti

density


Input: Finer microstructure and Ti precipitation led to superior hardness, tensile and wear resistance of Monel K500 compared to FM 60.

Finer microstructure

Ti

Monel

precipitation

led

hardness

tensile

wear resistance


Input: The variation in microstructure-properties relationship with alloy composition is discussed.

variation

alloy


Input: We devised a novel method to embed sensors or integrated circuit (IC) chips into metal components by using a selective laser melting (SLM) process.

sensors

integrated circuit

components

metal

selective laser melting

SLM

process


Input: The concept of a protective layer is introduced to fabricate all parts without damaging the sensors during the laser scanning process.

protective layer

fabricate

sensors

laser scanning process


Input: The operation of sensors in the parts is analyzed from a computational analysis on the thermal influence of laser heat.

sensors

laser heat


Input: The fabricated metal parts show continuous microstructures including grains and phases between the base part and the new part formed after embedding the sensor despite the intermittent SLM process.

fabricated

grains

process

microstructures

sensor

SLM


Input: The embedded sensor operates properly when compared to bare sensors.

sensor

sensors


Input: Plastic circuit board-based IC components were embedded into an Inconel 718C turbine blade, which accurately distinguished three-dimensional vibration along the X, Y, and Z axes.

Plastic

Inconel

Y

components

turbine blade

accurately

three-dimensional


Input: Our results imply that the proposed process can open new avenues for SLM technology to realize metal components with a self-cognitive ability using integrated sensors.

process

SLM

metal

components

sensors


Input: Printed free-standing pure Au structure with feature sizes of smaller than 10 microns.

Au

feature sizes


Input: Combination of laser-induced forward transfer of pure metals and chemical etching.

pure metals

etching


Input: Approach allows fully overhanging structures and reduces substrate contamination.

overhanging structures

substrate


Input: Cu support structures can be selectively removed after LIFT-printing.

Cu

be


Input: A combined approach of laser-induced forward transfer (LIFT) and chemical etching of pure metal films is studied to fabricate complex, free-standing, 3-dimensional gold structures on the few micron scale.

etching

fabricate

pure metal

gold

micron


Input: A picosecond pulsed laser source with 515 nm central wavelength is used to deposit metal droplets of copper and gold in a sequential fashion.

pulsed laser

wavelength

droplets

fashion

metal

copper

gold


Input: After transfer, chemical etching in ferric chloride completely removes the mechanical Cu support leaving a final free-standing gold structure.

etching

mechanical

Cu

gold


Input: Unprecedented feature sizes of smaller than 10 μm are achieved with surface roughness of 0.3 to 0.7 μm.

feature sizes

surface roughness


Input: Formation of interfacial mixing volumes between the two metals is not found confirming the viability of the approach.

mixing

metals


Input: Additive manufacturing promises to revolutionize manufacturing industries.

Additive manufacturing

manufacturing

industries


Input: However, 3D printing of novel build materials is currently limited by constraints inherent to printer designs.

3D printing

build materials

printer

designs


Input: In this work, a bench-top powder melt extrusion (PME) 3D printer head was designed and fabricated to print parts directly from powder-based materials rather than filament.

bench-top

fabricated

melt extrusion

PME

print

3D printer head

designed

powder-based materials

filament


Input: The final design of the PME printer head evolved from the Rich Rap Universal Pellet Extruder (RRUPE) design and was realized through an iterative approach.

design

design

PME printer head

Universal Pellet Extruder

iterative approach


Input: The PME printer was made possible by modifications to the funnel shape, pressure applied to the extrudate by the auger, and hot end structure.

PME printer

auger

hot end structure

pressure

extrudate


Input: Through comparison of parts printed with the PME printer with those from a commercially available fused filament fabrication (FFF) 3D printer using common thermoplastics poly (lactide) (PLA), high impact poly (styrene) (HIPS), and acrylonitrile butadiene styrene (ABS) powders (< 1 mm in diameter), evaluation of the printer performance was performed.

PME printer

3D printer

printer

fused filament fabrication

FFF

mm

thermoplastics

PLA

HIPS

acrylonitrile butadiene styrene

ABS

powders

impact

diameter

performance


Input: For each build material, the PME printed objects show comparable viscoelastic properties by dynamic mechanical analysis (DMA) to those of the FFF objects.

build material

PME

FFF

viscoelastic properties

dynamic mechanical analysis

DMA


Input: However, due to a significant difference in printer resolution between PME (X–Y resolution of 0.8 mm and a Z-layer height calibrated to 0.1 mm) and FFF (X–Y resolution of 0.4 mm and a Z-layer height of 0.18 mm), as well as, an inherently more inconsistent feed of build material for PME than FFF, the resulting print quality, determined by a dimensional analysis and surface roughness comparisons, of the PME printed objects was lower than that of the FFF printed parts based on the print layer uniformity and structure.

printer resolution

resolution

resolution

Z-layer height

feed

print layer

PME

mm

mm

FFF

mm

mm

PME

FFF

PME

FFF

Z-layer height calibrated

dimensional analysis

as

as

build material

print quality

structure

surface roughness


Input: Further, due to the poorer print resolution and inherent inconsistent build material feed of the PME, the bulk tensile strength and Young’ s moduli of the objects printed by PME were lower and more inconsistent (49.2 ± 10.7 MPa and 1620 ± 375 MPa, respectively) than those of FFF printed objects (57.7 ± 2.31 MPa and 2160 ± 179 MPa, respectively).

print resolution

build material

s

PME

PME

FFF

tensile strength

MPa

MPa

MPa

MPa


Input: Nevertheless, PME print methods promise an opportunity to provide a platform on which it is possible to rapidly prototype a myriad of thermoplastic materials for 3D printing.

PME

3D printing

platform

prototype

thermoplastic materials


Input: Effects of laser conditions on part qualities of a near-eutectic Al-Fe alloy fabricated via laser powder bed fusion was investigated.

laser

Al-Fe alloy

laser powder bed fusion


Input: The much refined microstructure consisting of nano-scaled Al-Fe intertmetallics with different size and morphology was observed.

microstructure

morphology


Input: P·v-1/2 based on deposited energy density model was proved to be a more appropriate design parameter.

energy density

be

design


Input: An estimated threshold value of P·v-1/2 for fabricating satisfactory Al-2.5Fe (mass%) alloy parts could be identified.

fabricating

alloy

be


Input: This study focused on additive manufacturing (AM) of the Al–Fe binary alloy samples with a near-eutectic composition of 2.5 mass% Fe using the laser powder bed fusion (LPBF) process.

additive manufacturing

AM

laser powder bed fusion

LPBF

binary

composition

process

alloy

Fe


Input: The melt pool depth, relative density, and hardness of LPBF-fabricated Al–2.5Fe alloy samples under different laser power (P) and scan speed (v) conditions were systematically examined.

melt pool depth

laser power

scan speed

relative density

hardness

alloy

P

v


Input: The results provided optimum laser parameter sets (P = 204 W, v ≤ 800 mms-1) for the fabrication of dense alloy samples with high relative densities > 99%.

laser

P

v

alloy

fabrication

relative densities


Input: Additionally, Pv-1/2, which is based on the deposited energy density model, was found to be a more appropriate parameter for additively manufacturing Al–2.5Fe alloy samples, and using it to simplify the relative densities of the samples made the determination of a threshold value for the laser parameters required to fabricate dense alloy samples.

energy density

be

alloy

alloy

parameter

samples

manufacturing

fabricate

relative densities

laser


Input: The microstructural and crystallographic characterization of the LPBF-built Al–2.5Fe alloy samples revealed a characteristic microstructure consisting of multi-scan melt pools that resulted from local melting and rapid solidification owing to laser irradiation during the LPBF process.

microstructural

microstructure

alloy

melt pools

melting

rapid solidification

irradiation

LPBF

laser


Input: Furthermore, a number of columnar grains with a mean width of ∼ 21 μm elongated along the building direction were also observed in the α-Al matrix.

columnar grains

building direction


Input: Numerous nano-sized particles of the metastable Al6Fe intermetallic phase with a mean size < 100 nm were finely dispersed in the α-Al matrix.

particles

metastable

intermetallic


Input: The hardness of the refined microstructure produced by the LPBF process was high at ∼ 90 HV, which is more than twofold higher than that of conventionally casted alloys that contain the coarsened plate-shaped Al13Fe4 intermetallic phase in equilibrium with the α-Al matrix.

hardness

microstructure

equilibrium

LPBF

alloys

intermetallic


Input: In-situ monitoring of metal additive manufacturing (AM) processes is a key issue to determine the quality and stability of the process during the layer-wise production of the part.

In-situ

processes

quality

process

metal additive manufacturing

AM

production

stability


Input: The quantities that can be measured via in-situ sensing can be referred to as “process signatures”, and can represent the source of information to detect possible defects.

be

be

as

in-situ

process

defects

source


Input: Most of the literature on in-situ monitoring of Laser Power Bed Fusion (LPBF) processes focuses on the melt-pool, laser track and layer image as source of information to detect the onset of possible defects.

in-situ

processes

image

defects

Laser Power Bed Fusion

LPBF

laser

layer

as


Input: High-speed image acquisition, coupled with image segmentation and feature extraction, is used to estimate different statistical descriptors of the spattering behaviour along the laser scan path.

image

image

feature extraction

laser scan


Input: A logistic regression model is developed to determine the ability of spatter-related descriptors to classify different energy density conditions corresponding to different quality states.

regression model

quality

energy density


Input: This is why future research on spatter signature analysis and modelling is highly encouraged to improve the effectiveness of in-situ monitoring tools.

research

effectiveness

in-situ

spatter

modelling

tools


Input: The metal additive manufacturing industry is rising and so is the interest in new lattice structures with unique mechanical properties.

metal additive manufacturing

industry

lattice structures

mechanical properties


Input: Many studies have already investigated lattice structures with different geometries and their influence on mechanical properties, but little is known about the effect of specific processing characteristics that are inherent to metal additive manufacturing.

lattice structures

geometries

mechanical properties

metal additive manufacturing


Input: Therefore this study investigates the effect of two crucial steps in the manufacturing process: the build orientation selection and heat treatment.

investigates

manufacturing process

heat treatment

build orientation


Input: In total the microstructure and static mechanical properties of five different orientations and three heat treatment conditions were evaluated using Ti6Al4V diamond like lattice structures.

microstructure

mechanical properties

orientations

heat treatment

Ti6Al4V diamond

lattice structures


Input: The results show a significant decrease in mechanical strength for samples that are built diagonally and a transformation of the microstructure after a HIP (hot isostatic pressing) treatment, resulting in a lower maximum strength, but higher ductility.

mechanical strength

strength

ductility

samples

microstructure

HIP

hot isostatic pressing


Input: In general, horizontal struts should be avoided during manufacturing, unless the applied load after manufacturing can be properly supported by other struts.

horizontal struts

be

be

manufacturing

manufacturing

struts


Input: Both a stress relief heat treatment and a HIP treatment can be used in statically loaded applications, whereas a HIP treatment is believed to be beneficial for dynamically loaded applications.

stress

heat treatment

HIP

HIP

be

be


Input: This study enables an appropriate selection of build orientation and heat treatment of lattice structures for different applications.

build orientation

heat treatment

lattice structures


Input: We report the design of a metal powder bed fusion system for in-situ monitoring of the build process during additive manufacture.

design

metal powder bed fusion

additive manufacture

in-situ

build


Input: Its open-architecture design was originally determined to enable access for x-rays to the melt pool, but it also provides access to the build area for a range of other in-situ measurement techniques.

design

x-rays

in-situ

melt pool

build area

range


Input: The system is sufficiently automated to enable single tracks and high-density, multiple layer components to be built.

layer

components

be


Input: It is easily transportable to enable measurements at different measurement facilities and its modular design enables straightforward modification for the specific measurements being made.

measurement

modular

design


Input: We demonstrate that the system produces components with > 99% density.

components

density


Input: Hence the build conditions are representative to observe process fundamentals and to develop process control strategies.

build

process

process control


Input: In this work a finite-element framework for the numerical simulation of the heat transfer analysis of additive manufacturing processes by powder-bed technologies, such as Selective Laser Melting, is presented.

framework

heat transfer

technologies

numerical simulation

Laser

additive manufacturing processes

as


Input: These kind of technologies allow for a layer-by-layer metal deposition process to cost-effectively create, directly from a CAD model, complex functional parts such as turbine blades, fuel injectors, heat exchangers, medical implants, among others.

technologies

layer-by-layer

deposition process

CAD model

as

heat exchangers

medical implants


Input: The numerical model proposed accounts for different heat dissipation mechanisms through the surrounding environment and is supplemented by a finite-element activation strategy, based on the born-dead elements technique, to follow the growth of the geometry driven by the metal deposition process, in such a way that the same scanning pattern sent to the numerical control system of the AM machine is used.

model

heat dissipation

geometry

metal deposition

elements

scanning pattern

numerical control

AM machine


Input: An experimental campaign has been carried out at the Monash Centre for Additive Manufacturing using an EOSINT-M280 machine where it was possible to fabricate different benchmark geometries, as well as to record the temperature measurements at different thermocouple locations.

experimental

Additive Manufacturing

fabricate

machine

thermocouple

benchmark

as

as

temperature


Input: The experiment consisted in the simultaneous printing of two walls with a total deposition volume of 107 cm3 in 992 layers and about 33,500 s build time.

experiment

deposition

s

build time


Input: A large number of numerical simulations have been carried out to calibrate the thermal FE framework in terms of the thermophysical properties of both solid and powder materials and suitable boundary conditions.

numerical simulations

FE

powder materials

properties

boundary conditions


Input: Furthermore, the large size of the experiment motivated the investigation of two different model reduction strategies: exclusion of the powder-bed from the computational domain and simplified scanning strategies.

experiment

model

computational domain

scanning strategies


Input: In August 2018, a demonstration/experiment was performed in Champaign, Illinois USA, at the Engineer Research and Development Center Construction Engineering Research Laboratory (ERDC-CERL) looking at the continuous printing of a 512 ft2 (47.6 m2) reinforced additively constructed concrete (RACC) building.

Research

Research Laboratory

reinforced

Construction

concrete


Input: Previously, in July of 2017, a more traditional building was 3D printed using a discontinuous concrete printing approach.

3D printed

concrete printing


Input: These demonstrations were performed to determine the feasibility of using additively constructed concrete (ACC) as a material for vertical structural elements.

feasibility

vertical

concrete

as

material

elements


Input: This study explores the differences and similarities of ACC with conventional concrete construction and concrete masonry unit construction.

concrete

concrete

construction


Input: To validate the feasibility of ACC a cost comparison analysis was performed comparing the construction methods used in these demonstrations to conventional concrete masonry unit and cast-in-place concrete construction.

feasibility

construction

concrete

concrete


Input: Layered Assembly is a voxel-based additive manufacturing method in which premanufactured voxels serve as the feedstock for producing multi-material parts.

Assembly

additive manufacturing

voxels

multi-material

as

feedstock


Input: Electrodes were nominally designed for grasping voxels of 3 × 3 mm cross-section.

Electrodes

designed

voxels

mm


Input: Electrostatic field simulations were performed in COMSOL Multiphysics for both single electrodes, and 2 × 2 electrode arrays.

simulations

electrodes

electrode


Input: The selective gripping capability of the electrode arrays was tested at voltages in the 75–800 V range and applied to both polymer and metallic voxels.

electrode

V

polymer

metallic

range


Input: A comparison of electrode performance in terms of geometry revealed that comb-shaped electrodes were superior, due to ≈100% reliability when operating in the 600–800 V range.

electrode

electrodes

geometry

reliability

V

range


Input: Lack-of-fusion flaws can occur in powder bed fusion (PBF) additive manufacturing of metal components.

flaws

powder bed fusion

PBF

additive manufacturing

metal

components


Input: This paper demonstrates a method for detecting such flaws by monitoring the fabrication of every layer before and after laser scanning with high resolution optical imaging.

flaws

fabrication

layer

high resolution

laser

imaging


Input: A binary template is created from the sliced 3D model of the part.

binary

3D model


Input: Using this template the optical image data is indexed to the part geometry.

template

optical

image data

geometry


Input: The indexed image data is used to detect anomalies in the powder layer before laser scanning and in the solidified material after scanning.

image data

anomalies

scanning

powder

material

layer

laser


Input: Lack-of-fusion defects are identified from optical data by correlating multiple images with different lighting conditions and from multiple layers.

defects

data

images

optical


Input: Pyrometry showed an increase in intensity in CO2 atmosphere over Ar atmosphere.

Pyrometry

Ar


Input: At low levels of reactive gas atmospheres oxygen loss from spatter dominates.

gas

oxygen

spatter


Input: Oxygen increased in samples from 0.016 wt.% in Ar to 0.1 wt.% in CO2.

Oxygen

samples

Ar


Input: Average in-situ particle size in the samples were ∼40 nm.

Average

particle

samples


Input: There was a 20% increase in yield strength when samples were produced under CO2.

yield strength

samples


Input: Traditionally, reactive gases such as oxygen (O2) and carbon dioxide (CO2) have been avoided during laser powder bed fusion (L-PBF) of metals and alloys based on the notion that it may lead to defect formation and poor properties.

as

carbon

metals

alloys

lead

laser powder bed fusion

L-PBF

defect

properties


Input: Here we show that instead, these gases can be used to form sub-μm-sized oxide particles in-situ during the L-PBF process in an Fe-Cr-Al-Ti stainless steel and lead to improved room temperature and high-temperature mechanical properties.

be

oxide

stainless steel

lead

in-situ

mechanical properties

L-PBF

temperature


Input: We manufactured cube samples using pure Ar and various reactive gas atmospheres, namely an O2/Argon (Ar) mixture containing 0.2% O2 and CO2/Ar mixtures containing up to 100% CO2.

manufactured cube

gas

Ar

Ar


Input: Co-axial measurements of infrared radiation emitted from the melt pool showed correlation to the presence of O2 or CO2 in the gas mixture.

infrared

gas

melt pool


Input: Builds produced under CO2-containing atmosphere contained complex oxides with an average diameter of ∼40 nm, an Al-rich core and a Ti-rich shell.

Builds

oxides

average

core

shell


Input: Due to the high cooling rates typical to L-PBF, agglomeration of oxides and slag formation on the surface of the samples could almost be entirely avoided.

cooling rates

L-PBF

oxides

slag

be

surface

samples


Input: Compression tests at temperatures up to 800 °C showed that the samples produced in 100% CO2 have about 20% higher yield stress compared to samples produced in Ar.

Compression tests

temperatures

samples

samples

yield stress

Ar


Input: The paper concludes with a discussion of the formation mechanism of the observed oxides.

mechanism

oxides


Input: Our results show that in-situ reactions during additive manufacturing processes are a promising pathway to the synthesis of particle-reinforced alloys.

in-situ

additive manufacturing processes

alloys


Input: Additive manufacturing (AM) processes, such as Selective Laser Sintering (SLS), have enabled the fabrication of geometrically complicated designs.

Additive manufacturing

AM

Laser Sintering

SLS

fabrication

processes

as

designs


Input: However, undesired distortions due to thermally-induced residual stresses may lead to loss of tolerance or failure of the part.

residual stresses

lead

tolerance

failure


Input: One potential failure mode is buckling, particularly when realizing high aspect ratio features, like for infill, to minimize weight.

failure mode

buckling

high aspect ratio

infill

weight


Input: In this paper, we address distortions and part failures due to buckling by using a finite element model to predict residual stress distributions and sintering induced distortions.

buckling

residual stress

finite element model

distributions

sintering


Input: Initially, we conduct a transient thermal simulation to determine the Heat Affected Zone (HAZ), which is then used in the thermomechanical simulation.

transient

Heat Affected Zone

HAZ

thermomechanical

simulation

simulation


Input: In addition, we imposed perturbations on the mechanical mesh based on the buckling eigenmodes.

mechanical

buckling


Input: Finally, a thermomechanical viscoplastic analysis was performed layer-by-layer to obtain the final residual stress state and subsequent distortions that occur after cooling down to ambient temperature.

thermomechanical

layer-by-layer

residual stress

cooling

temperature


Input: A model was used to describe the evolution of porosity due to laser sintering, and then a model of the effects of porosity on the viscoplastic constitutive properties of the sintered material was used in the thermomechanical simulation.

model

evolution

model

properties

thermomechanical

porosity

porosity

laser sintering

sintered

material

simulation


Input: Modeling results are compared against experimental specimens using a Durelli (aka, Theta) specimen geometry fabricated with a 3D Systems ProX 200 Selective Laser Sintering (SLS) machine.

Modeling

experimental

geometry fabricated

3D Systems

Selective Laser Sintering

SLS

machine


Input: The geometry of the specimen represents an internal feature with a high aspect ratio that is prone to buckling, and the dimensions were modified based on the simulation results to confirm the ability of the modeling approach to provide accurate mitigation of buckling-induced distortions.

geometry

feature

high aspect ratio

dimensions

buckling

simulation

modeling

accurate


Input: This paper presents a process-microstructure finite element modeling framework for predicting the evolution of volumetric phase fractions and microhardness during laser directed energy deposition (DED) additive manufacturing of Ti6Al4V.

finite element

framework

evolution

phase fractions

microhardness

laser directed energy deposition

DED

additive manufacturing


Input: Based on recent experimental observations, the present microstructure evolution model is formulated to combine the formation and dissolution kinetics of grain boundary, Widmanstätten colony/basketweave, massive/martensitic alpha and beta phases of Ti6Al4V.

experimental

microstructure evolution

grain boundary


Input: The microstructure evolution algorithm is verified and embedded into a three-dimensional finite element process simulation model to simulate thermally driven phase transformations during DED processing of a Ti6Al4V thin-walled rectangular sample.

microstructure evolution

algorithm

three-dimensional

finite element

model

phase

sample

simulation

DED


Input: The simulated volumetric phase fractions and related microhardness distribution agree reasonably well with experimental measurements performed on the sample.

phase fractions

microhardness

distribution

experimental

sample


Input: Thus the proposed simulation model could be useful for designers to understand and control process-microstructure-property relationships in a DED-processed part.

simulation

model

be


Input: The present research work has investigated the synthesis of ceramic structures based on inorganic, spherical-hollow microballoons using a binder jet printing process.

research

ceramic

binder

printing process


Input: Binder jet printing is a process that allows the synthesis process of complex and intricate parts with minimal waste of the feedstock material.

Binder

feedstock material

process

process


Input: The ceramic microballoons here investigated were based on a mullite derivative.

ceramic

mullite


Input: The printed ceramic parts were cured and sintered as the precursor templates for metal matrix syntactic foams (MMSFs).

ceramic

as

precursor

cured

sintered

metal matrix


Input: The MMSFs were manufactured by infiltrating the printed ceramic templates by molten aluminum.

manufactured

infiltrating

ceramic

aluminum


Input: The flexural strength of the cured, sintered, and infiltrated structures were also investigated.

flexural strength

cured

sintered


Input: It is proposed that binder jet printing followed by a sintering and pressureless infiltration process represents an advantageous technology for designing complex MMSF structures.

binder

sintering

infiltration

technology


Input: The fused coating process is a new material jetting additive manufacturing technology that proposes to solve the problem of high cost, low efficiency and high material requirements of laser-based process and electron beam process.

fused

process

electron beam

coating

material jetting

additive manufacturing

material


Input: The structure and operating principles of the fused coating machine are explained in this paper.

structure

fused

coating


Input: Sn63Pb37 is taken as the experimental material because of its low melting temperature, small surface tension coefficient and high viscosity.

as

experimental

melting temperature

surface tension

viscosity


Input: Tensile test specimens were made both parallel and perpendicular to the forming trajectory.

Tensile test

forming


Input: Tensile strengths were measured and the corresponding fractographies were observed.

Tensile strengths


Input: It is found that large plastic deformation has occurred before the fracture, and the plasticity of fused components that the tensile direction parallel to the forming trajectory, is higher.

plastic deformation

plasticity

tensile

fracture

fused

components

forming


Input: The densification degree of fused coating component is measured by the drainage method.

densification

fused

coating


Input: The average value is up to 99.78% which indicates that the internal structure is indistinguishable from extruded Sn63Pb37.

average

internal structure

extruded


Input: The Vickers hardness of the fused coated component and raw casted material were tested by 5 points respectively, the results showed that the average Vickers hardness of the fused coating component is 14.6% higher than the casted one.

Vickers hardness

hardness

fused

average

fused

coated

coating

material


Input: Cellular materials, such as foams, can be used as load bearing members in civil construction and as protective energy absorbing structures for personnel and equipment.

Cellular materials

as

be

as

as

construction

equipment


Input: In the present study, novel lightweight closed-cell structures were designed, and their mechanical properties and collapse mechanisms were investigated through a combination of experimental validation and finite element (FE) simulations.

lightweight

mechanical properties

experimental

finite element

designed

FE

simulations


Input: Selected porous structure designs were manufactured from acrylonitrile butadiene styrene (ABS) using additive manufacturing technology.

porous

designs

manufactured

acrylonitrile butadiene styrene

ABS

additive manufacturing


Input: These 3D printed structures were subjected to quasi-static loading to determine the dependence of their elastic and plastic responses from their topological features.

3D printed

quasi-static

elastic

plastic


Input: Deformation mechanisms were elucidated through quasi-static compression experiments and FE modelling.

Deformation

quasi-static

compression

FE


Input: The appropriate distribution of the base material in the designed closed-cell structures inherits the merits of uniform stress distribution and large deformations that lead to reaching high strengths and desirable energy absorption efficiencies.

distribution

deformations

material

lead

designed

stress distribution

strengths

energy absorption


Input: The effects of relative density and cell shape were studied in detail from elastic loading through the large plastic strain densification regions.

relative density

elastic

cell

plastic

densification


Input: The effects of cellular architecture on deformation mechanisms and energy absorption capabilities demonstrated the possibility of enhancing energy absorption efﬁciencies with appropriate design criteria.

architecture

deformation

energy absorption

energy absorption

design


Input: Based on the experimental and numerical analyses, the most efficient energy absorbing closed-cell structure was proposed.

experimental

structure


Input: The performance enhancement of parts produced using Selective Laser Melting (SLM) is an important goal for various industrial applications.

performance

Selective Laser Melting

SLM

industrial


Input: In order to achieve this goal, obtaining a homogeneous microstructure and eliminating material defects within the fabricated parts are important research issues.

homogeneous

defects

fabricated

research

material


Input: The objective of this experimental study is to evaluate the effect of thermal post-processing of AlSi10Mg parts, using recycled powder, with the aim of improving the microstructure homogeneity of the as-built parts.

experimental

post-processing

recycled

microstructure

powder


Input: This work is essential for the cost-effective additive manufacturing (AM) of metal optics and optomechanical systems.

additive manufacturing

AM

metal


Input: To achieve this goal, a full characterization of fresh and recycled powder was performed, in addition to a microstructure assessment of the as-built fabricated samples.

recycled

microstructure

fabricated

powder


Input: Annealing, solution heat treatment (SHT) and T6 heat treatment (T6 HT) were applied under different processing conditions.

Annealing

solution heat treatment

heat treatment


Input: A micro-hardness map was developed to assist in the selection of the optimized post-processing parameters in order to satisfy the design requirements of the part.

post-processing parameters

design


Input: Thermal barrier coatings (TBC) are regularly used today to protect and extend the service life of several superalloys which are extensively used in high temperature applications.

Thermal barrier coatings

TBC

service life

superalloys

temperature


Input: The existing TBCs are typically between 0.1 to 0.5 mm in thickness, are deposited on metal substrates using plasma spray or electron beam vapor deposition, and can reduce temperatures at the substrate surface by up to 300 °C.

TBCs

mm

plasma spray

metal

substrate

electron beam

deposition

temperatures


Input: For greater temperature reductions there is a need for thicker TBCs.

temperature

TBCs


Input: The building of thick TBCs has to date been stymied by poor adhesion, and cracking during deposition.

TBCs

adhesion

cracking

deposition


Input: It has been suggested that a functionally graded approach may reduce the residual stresses which result in these defects.

functionally graded

defects

residual stresses


Input: To date there have been few reports on the deposition of ceramic or cermet coatings using laser AM and none have reported on the phase stability of ceramic particles post-deposition.

deposition

phase

ceramic

cermet

ceramic

laser

AM


Input: This paper is a first report on the phase stability of ceramic particles following the compositional segregation of elements during deposition using a powder feed additive manufacturing process.

phase

segregation

deposition

ceramic

elements

powder

feed

additive manufacturing process


Input: Functionally graded (FG), thick TBCs (> 3 mm) consisting of Inconel 625 (IN625) and yttria-partially stabilized zirconia (8YSZ) were deposited on an A516 steel substrate via laser direct energy deposition (LDED).

Functionally graded

TBCs

mm

direct energy deposition

Inconel 625

zirconia

steel

laser


Input: Good interfaces were observed between the bond coat (BC) and first cermet layer and between the graded cermet layers.

bond coat

cermet

cermet


Input: However, cermet layers deposited with 10 wt.% or more YSZ developed a thin layer of YSZ on the surface.

cermet

YSZ

YSZ

layer

surface


Input: The thin layer of YSZ greatly hindered additional deposition of new cermet layers.

layer

YSZ

cermet

deposition


Input: In cermet layers that did exhibit good interfaces, fine, re-solidified, YSZ particles were homogenously distributed within the Inconel 625 matrix.

cermet

YSZ

Inconel 625

particles


Input: The YSZ particles exhibited a tetragonal lattice structure and were depleted of yttrium.

YSZ

yttrium

particles

tetragonal lattice structure


Input: In contrast, the thin YSZ layer formed on a cermet surface showed no yttrium depletion.

YSZ

cermet

yttrium

layer


Input: Some of the primary barriers to widespread adoption of metal additive manufacturing (AM) are persistent defect formation in built components, high material costs, and lack of consistency in powder feedstock.

metal additive manufacturing

AM

defect

consistency

components

powder feedstock

material


Input: To generate more reliable, complex-shaped metal parts, it is crucial to understand how feedstock properties change with reuse and how that affects build mechanical performance.

complex-shaped

performance

feedstock

build


Input: Powder particles interacting with the energy source, yet not consolidated into an AM part can undergo a range of dynamic thermal interactions, resulting in variable particle behavior if reused.

Powder particles

source

AM part

range

dynamic

particle


Input: In this work, we present a systematic study of 316L powder properties from the virgin state through thirty powder reuses in the laser powder bed fusion process.

powder

powder

laser powder bed fusion


Input: Thirteen powder characteristics and the resulting AM build mechanical properties were investigated for both powder states.

powder

powder

AM

mechanical properties


Input: Results show greater variability in part ductility for the virgin state.

variability

ductility


Input: The feedstock exhibited minor changes to size distribution, bulk composition, and hardness with reuse, but significant changes to particle morphology, microstructure, magnetic properties, surface composition, and oxide thickness.

feedstock

oxide

distribution

composition

particle

morphology

microstructure

properties

surface

composition

hardness


Input: Additionally, sieved powder, along with resulting fume/condensate and recoil ejecta (spatter) properties were characterized.

powder

spatter

properties


Input: It was discovered that spatter leads to formation of single crystal ferrite through large degrees of supercooling and massive solidification.

spatter

ferrite

supercooling

solidification


Input: Ferrite content and consequently magnetic susceptibility of the powder also increases with reuse, suggesting potential for magnetic separation as a refining technique for altered feedstock.

Ferrite

powder

as

feedstock

magnetic susceptibility

magnetic separation


Input: Tensile stress in selective laser melted (SLM) stainless steel 316 (SS316) bars was studied with neutron imaging methods for measurement of attenuation, scattering, and diffraction.

Tensile stress

selective laser melted

SLM

stainless steel

neutron

imaging

measurement

diffraction


Input: The hypotheses for stress failure includes modifications to both the grain structure and residual porosity.

stress

porosity

failure

grain structure

residual


Input: Neutron Bragg edge imaging showed a change in crystallographic structure and/or texture at a pre-existing fracture, but did not provide evidence for presumptive crack formation.

Neutron

structure

fracture

imaging

texture


Input: A Talbot-Lau grating-based neutron interferometer yielded better than 100 μm spatial resolution for the attenuation images and was tuned to an autocorrelation scattering length of 1.97 μm for the dark-field (scattering) images.

neutron

images

images

resolution


Input: The interferometry imaging was performed with samples parallel and perpendicular to the linear grating, allowing assessment of scattering along and perpendicular to the additive manufacturing build direction.

interferometry

samples

imaging

additive manufacturing


Input: In the 3D tomography dark-field volume of a tensile stressed bar, features were observed that suggested possible sites of crack formation.

volume

tensile


Input: The features were quantified with line probes and found to be reproducible over three tomography experiments.

probes

be


Input: After imaging, the half-stressed bar was pulled to failure; the fracture point is correlated with a feature in the line probe having enhanced neutron scattering.

imaging

failure

fracture

correlated

feature

probe

neutron scattering


Input: Neutron interferometry, particularly the dark-field imaging modality, emerges as a powerful non-destructive method for detecting early crack formation in additive manufactured components.

Neutron

interferometry

imaging

as

additive manufactured


Input: Additive Manufacturing (AM) is a method of joining metal/non-metals or composites layer by layer using different energy sources.

Additive Manufacturing

AM

joining

composites

layer


Input: Among the various AM processes, laser-based powder bed fusion (LPBF) is very popular, in which geometrically complex structures can be manufactured directly from CAD models.

AM processes

powder bed fusion

LPBF

complex structures

be

CAD models


Input: One of the least investigated areas in LPBF is the fatigue property of LPBF produced stainless steel parts, which find a variety of engineering and medical applications.

areas

LPBF

LPBF

fatigue

stainless steel

engineering

medical applications


Input: In actual service conditions, many engineering components undergo variable cyclic loadings.

engineering

components

cyclic loadings


Input: Therefore, in order to widen industrial applications of LPBF process, effects of variable amplitude loading under both zero and tensile mean stresses on the fatigue life of LPBF produced 15-5 precipitation hardened stainless steel parts have been examined in the present study.

industrial

LPBF

LPBF

precipitation hardened

tensile

fatigue life

steel


Input: Further, different modes of failure, effects of load sequences on fatigue life and the cumulative damage during the process have also been studied.

failure

process

fatigue life

damage


Input: Fracture surfaces were studied using Scanning Electron Microscopy to investigate the mode of failures and completely different fracture surface morphologies for these two cases explain the observed difference in number of cycles to failure with the reversal of the load sequence.

Fracture

fracture

morphologies

failure

Scanning Electron Microscopy


Input: Recent advances in X-ray computed tomography (XCT) have allowed for measurement resolutions approaching the point where XCT can be used for measuring surface topography.

X-ray computed tomography

measurement

be

surface topography


Input: These advances make XCT appealing for measuring hard-to-reach or internal surfaces, such as those often present in additively manufactured parts.

surfaces

as

additively manufactured


Input: To demonstrate the feasibility and potential of XCT for topography measurement, topography datasets obtained using two XCT systems are compared to those acquired using coherence scanning interferometry and focus variation microscopy.

feasibility

scanning interferometry

variation

topography

measurement

topography

microscopy


Input: A hollow Ti6Al4V part produced by laser powder bed fusion is used as a measurement artefact.

as

laser powder bed fusion

measurement


Input: The artefact comprises two component halves that can be separated to expose the internal surfaces.

component

be

surfaces


Input: Measured surface datasets are accurately aligned and similarly cropped, and compared by various qualitative and quantitative means, including the computation of ISO 25178-2 areal surface texture parameters, commonly used in part quality assessment.

surface

qualitative

quantitative

computation

parameters

quality

accurately

ISO 25178-2

surface texture


Input: Results show that XCT can non-destructively provide surface information comparable with more conventional surface measurement technologies, thus representing a viable alternative to more conventional measurement, particularly appealing for hard-to-reach and internal surfaces.

surface

surface

surfaces

measurement

measurement


Input: Low-cost GMAW-based 3-D printing slicing needed for diverse users.

slicing


Input: Upgraded free and open source CuraEngine into MOSTMetalCura.

source


Input: New slicer track counts, avoid overlaps, infill to enable continous bead.

slicer

infill

bead


Input: Also includes variable pauses, control of welder and set wire feed.

set

feed


Input: The slicer enables 1 mm resolution printing of ER70S-6 steel.

slicer

mm


Input: Low-cost gas metal arc welding (GMAW) -based 3-D printing has proven effective at additive manufacturing steel and aluminum parts.

gas metal arc welding

GMAW

additive manufacturing

aluminum


Input: To enable automated slicing a 3-D model and generating G-code for an acceptable path for GMAW 3-D printing, this paper reports on upgrading of the free and open source CuraEngine.

slicing

G-code

GMAW

source


Input: The new slicer, MOSTMetalCura, provides the following novel abilities necessary for GMAW 3-D printing: i) change the perimeter metric from width to track count, ii) avoid movement that overlaps previous weld beads, iii) have infill start immediately after the perimeter finished and in the direction that eliminates translations, iv) add a variable pause between layers to allow for substrate cooling, v) configure GPIO pins to turn on/off the welder, and vi) set optimized wire feed speed and voltage of the welder based on printing speed, layer height, filament diameter, and tool track width.

slicer

GMAW

cooling

weld beads

infill

feed

printing speed

layer height

filament diameter

substrate

v

set

tool


Input: The process for initiating these changes are detailed and the new slicer is used to help improve the function of the printer for ER70S-6 steel.

process

slicer

printer


Input: To find the printing function with the smallest bead width based on volume of material, the line width, layer height, and printing speed are varied to provide wire feed speed calculated by MOSTMetalCura, then the settings are used to print 3-D models.

bead width

volume

material

layer height

printing speed

feed

print


Input: The results of 3-D printing three case study objects of increasing geometric complexity using the process methodology improvements presented, which show resolution of 1 mm bead widths.

case study

complexity

process methodology

resolution

mm

bead widths


Input: In the current study, cylindrical samples of AlSi10Mg alloy were fabricated using direct metal laser sintering (DMLS) technique in vertical and horizontal directions.

cylindrical

fabricated

vertical

AlSi10Mg alloy

direct metal laser sintering

DMLS


Input: The microstructure of the samples was analyzed using scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy.

microstructure

samples

scanning electron microscopy

electron backscatter diffraction

transmission electron microscopy


Input: It was observed that, by changing the building direction from vertical to horizontal, columnar to equiaxed transition (CET) occurred in the alloy.

building direction

vertical

transition

alloy


Input: While 75% of the grains in the vertical sample were columnar, by changing the direction to horizontal, 49% of the grains evolved with columnar shape and 51% of them were equiaxed.

grains

vertical sample

grains


Input: Moreover, the texture of DMLS-AlSi10Mg alloy changed due to CET.

texture

alloy


Input: While {001} fiber texture evolved in the vertical sample, the < 001 > direction tilted away from the building direction in the horizontal one.

fiber

vertical sample

building direction


Input: Using the fundamentals of solidification and constitutional undercooling, the solidification behavior of AlSi10Mg alloy during DMLS process was modeled.

solidification

solidification

AlSi10Mg alloy

DMLS


Input: It was observed that, the determinant parameter in CET during DMLS of AlSi10Mg alloy is the angle between the nominal growth rate and < hkl > direction of the growing dendrite, which is controlled by the geometry and building direction of the sample.

parameter

geometry

sample

DMLS

AlSi10Mg alloy

dendrite

building direction


Input: Further TEM studies confirmed that, CET alters the shape and coherency of Si precipitates and dislocation density inside the α-Al dendrites in DMLS-AlSi10Mg alloy.

TEM

Si

precipitates

alloy

dislocation density

dendrites


Input: Metal additive manufacturing, despite of offering unique capabilities e.g.

Metal additive manufacturing


Input: unlimited design freedom, short manufacturing time, etc., suffers from raft of intrinsic defects.

design freedom

defects

manufacturing

raft


Input: Porosity is of the defects which can badly deteriorate a part’ s performance.

Porosity

defects

performance

s


Input: To this end, in this work a combined numerical and experimental approach has been used to analyze the formation, evolution and disappearance of keyhole and keyhole-induced porosities along with their initiating mechanisms, during single track L-PBF of a Ti6Al4V alloy.

experimental

evolution

porosities

L-PBF

Ti6Al4V alloy


Input: In this respect, a high-fidelity numerical model based on the Finite Volume Method (FVM) and accomplished in the commercial software Flow-3D is developed.

high-fidelity

model

Finite Volume Method

software


Input: The model accounts for the major physics taking place during the laser-scanning step of the L-PBF process.

model

physics

step

L-PBF


Input: The results show that during the keyhole regime, the heating rises dramatically compared to the shallow-depth melt pool regime due to the large entrapment of laser rays in the keyhole cavities.

heating

melt pool

laser


Input: Also a detailed parametric study is performed to investigate the effect of input power on thermal absorptivity, heat transfer and melt pool anatomy.

power

heat transfer

melt pool


Input: Furthermore, an X-ray Computed Tomography (X-CT) analysis is carried out to visualize the pores formed during the L-PBF process.

X-ray Computed Tomography

pores

L-PBF


Input: It is shown, that the predicted shape, size and depth of the pores are in very good agreement with those found by either X-CT or optical and 3D digital microscopic images.

predicted

images

pores

optical


Input: Selective Laser Melting (SLM) is a metal additive manufacturing process where parts are fabricated from metal powder based on CAD data.

Selective Laser Melting

SLM

metal additive manufacturing

fabricated

metal powder

CAD


Input: Selection of the best process parameters for the pulsed SLM processes is a fundamental problem due to the increased number of parameters that have a direct impact on the melt pool compared to the continuous SLM processes.

process parameters

processes

parameters

impact

processes

SLM

SLM

melt pool


Input: In previous studies, volumetric energy density or scan speed have been used as control variables for applied energy.

energy density

scan speed

as


Input: In this paper, the process parameters (laser power, exposure time, point distance and hatching distance) were considered individually, in addition to particle size distribution and layer thickness.

process parameters

exposure

particle size distribution

laser power

layer thickness


Input: The Taguchi experimental design method was used to determine and optimise the effect of the selected input parameters.

experimental design

parameters


Input: The effect of exposure time and its correlation with layer thickness and particle size distribution was then investigated.

exposure

particle size distribution

layer thickness


Input: The results show the best combination of process parameters which can provide fully or near fully dense parts.

process parameters

fully dense


Input: The results also show the minimum exposure time that can be used with different powder types and layer thicknesses.

exposure

be

powder

layer thicknesses


Input: The paper concludes with a study which shows the part location has a significant impact on sample quality.

part location

impact

sample

quality


Input: X-ray microtomography can be used to characterise objects undergoing fabrication by additive manufacturing.

X-ray microtomography

be

fabrication

additive manufacturing


Input: During the layer-by-layer building process, it can provide key information about geometry, roughness and it can even reveal typical defects such as lack-of-fusion porosity, gas pores or cracks.

layer-by-layer

geometry

defects

gas

building process

roughness

porosity

as


Input: In the present work, we describe our custom-designed additive manufacturing chamber allowing in situ 3D-non-destructive characterisation to be performed during layer-by-layer construction using synchrotron X-ray microtomography.

additive manufacturing

in situ

layer-by-layer

be

construction

synchrotron


Input: Scans before (subsequently to powder deposition) and after local laser melting are acquired for every layer.

powder

deposition

laser

layer


Input: Among the most popular additive manufacturing processes for metals, Powder bed fusion technology involves a layer by layer manufacturing approach utilizing a high power source, such as a laser or an electron beam, interacting with the metal powder on selected surfaces.

additive manufacturing processes

Powder bed fusion

metals

as

metal powder

layer by layer

electron beam

surfaces

power

laser


Input: Beam-powder interaction brings up a handful of phenomena affecting the quality of the final part in its volume and surface.

quality

volume

surface


Input: In this study, different surface features generated by Selective Laser Melting of an Al-Si7-Mg alloy are investigated and interpreted based on their morphology, microstructure and hardness to improve the general understanding of defect genesis.

surface

morphology

microstructure

defect

Selective Laser Melting

alloy

hardness


Input: Ballings, spatter particles and partially melted metal powders are distinguished by their morphology, size and microstructure.

spatter

particles

melted

morphology

microstructure

powders


Input: It is shown that these differences arise from different cooling rates during their generation.

cooling rates


Input: Ballings share the same microstructure with the bulk material both experiencing cooling in conduction mode.

microstructure

material

cooling


Input: Spatters and partially melted powders show coarser microstructure driven by solidification mainly ruled by convection and radiation during their flight in the inert atmosphere of the process chamber.

melted

microstructure

solidification

process

radiation


Input: Long production times, the associated high costs of the products and product size limitations belong among current issues of selective laser melting (SLM) technology.

production

selective laser melting

SLM

technology


Input: Hybrid products containing small and complex-shaped parts deposited by SLM on the forged, rolled or hot stamped semi-products could offer a practical solution to these limitations.

complex-shaped

solution

SLM


Input: Cylindrical hybrid parts were additively manufactured by depositing 18Ni300 maraging steel on the cylindrical semi-products of CMnAlNb low-alloy advanced high strength steel (AHSS).

Cylindrical

cylindrical

additively manufactured

maraging steel

steel

strength


Input: The AHSS was used either in forged and air cooled condition or after heat treatments typically used for inducing the TRIP (transformation induced plasticity) effect.

heat treatments

plasticity


Input: Various post-build heat treatments of the hybrid parts were performed.

heat treatments


Input: The mechanical properties of the hybrid parts were determined by hardness measurement across the interface and by a tensile test of the dissimilar joints.

mechanical properties

interface

hardness

tensile test


Input: All tensile samples fractured in the high-strength steel side, several millimetres from the interface.

tensile

samples

interface

steel


Input: Microstructure analysis of both materials and the interface region was carried out using light and scanning electron microscopes.

Microstructure

materials

interface

scanning electron microscopes


Input: The hybrid parts had the ultimate tensile strengths of 840−940 MPa, with total elongations of 12–19%.

ultimate tensile strengths

MPa


Input: The best combination of tensile strength and elongation was obtained with two-step heat treatment of the TRIP steel prior to additive manufacturing with no post-build heat treatment of the hybrid part.

tensile strength

elongation

heat treatment

additive manufacturing

heat treatment

TRIP steel


Input: In this paper, the potential of selective laser melting (SLM) of stainless steel CL 20ES powder was investigated with a focus on controlled fabrication of porous structures with strongly reduced pore sizes, i.e.

selective laser melting

SLM

fabrication

stainless steel

powder

CL

porous

pore sizes


Input: feature sizes significantly below conventional minimum SLM feature sizes.

feature sizes

feature sizes

SLM


Input: By controlling laser scan properties interacting with the powder bed directly, porous structures can be generated by selectively sintering powder particles.

laser scan

powder bed

porous

be

powder particles

sintering


Input: A wide range of porous samples was manufactured following this strategy, aiming to increase porosity while keeping pore sizes low.

range

pore sizes

porous

porosity

manufactured


Input: The effect of process parameters, including laser power and focal point positioning, was evaluated for a fibre laser operated in pulsed wave (PW) emission mode.

process parameters

fibre laser

laser power

emission


Input: The first part of this study focuses on characterization of key porous structure properties, i.e., porosity, average mass density, average pore sizes and structures at microscopic scales.

porous

porosity

density

properties

average

average


Input: The second part deals with the influence of porosity and pore sizes on thermal and fluid properties, i.e., the effective thermal conductivity (ETC) and wettability.

porosity

fluid properties

pore sizes

effective thermal conductivity

wettability


Input: We have quantified the directional dependence (build direction plane and scan direction plane) off the structural and thermophysical properties of porous structures.

build direction

properties

porous


Input: For a range of porosities and pore sizes, we have observed that porosity and surface morphology influence the thermal properties and contact angle of droplets on the printed surface.

range

pore sizes

porosities

porosity

surface morphology

thermal properties

droplets

surface

contact


Input: Thermal conductivity was measured and the associated analysis was compared with available models and correlations in literature.

Thermal conductivity


Input: The average thermal conductivity of fabricated porous structures was determined between 6-14 W/m·K and found to be a function of porosity.

average

fabricated

conductivity

porosity

be


Input: Furthermore, the capillary wicking performance of additively manufactured stainless steel porous structures having an average pore radius from 9 to 23 µm was determined.

performance

average

additively manufactured

steel

porous


Input: Typically, additive manufacturing (AM) processes are limited to a single material per build while many products benefit from the integration of multiple materials with varied properties.

additive manufacturing

AM

processes

materials

properties

material

build


Input: To achieve the benefits of multiple materials, the geometric freedom of AM could be used to build internal structures that emulate a range of different material properties such as stiffness, Poisson’ s ratio, and elastic limit using only a single build material.

materials

geometric freedom

material properties

AM

be

as

s

build material

build

range

elastic


Input: This paper examines a wide range of properties that can be achieved using diamond lattice structures manufactured from Nylon 12 with a commercial laser sintering (LS) process.

range

properties

manufactured

process

be

diamond

Nylon

laser sintering


Input: Stiffness and energy absorption were measured for all lattices and the stiffness response was compared to finite element analysis (FEA).

Stiffness

stiffness

energy absorption

lattices

finite element analysis


Input: Simulation shows agreement with experimental results over a stiffness range of four orders of magnitude once a correction factor is applied.

Simulation

experimental

stiffness

range

magnitude


Input: Experimental results also show a wide range of energy absorption for diamond lattice structures and a significant increase in the effective elastic limit of the build material, which compensates for the low ductility of many AM materials.

Experimental

range

energy absorption

diamond

build material

AM materials

elastic

ductility


Input: The elastic limit decreases with an increasing t/L ratio meanwhile the degradation under cyclic loading is relatively independent of the t/L ratio.

elastic

cyclic loading

degradation


Input: Extrapolating this data into lattice structures made from metal, these same structures could mimic a wide range of “fully” dense and porous materials with just the use of a single material.

data

lattice structures

dense and porous

metal

material

mimic

range


Input: Since the diamond lattice is a cellular structure, the voids can also be filled with other materials or structures to add secondary control of embedded functions such as energy storage and sensing.

diamond

be

as

cellular structure

voids

materials

sensing


Input: Laser wire deposits using Alloy 625 modified with 0.4 wt% B were manufactured on stainless steel 304 substrates.

Laser

Alloy

B

stainless steel

manufactured


Input: A layer boundary with a thickness of around 250 μm was formed between the layer cores during deposition.

layer

layer

boundary

cores

deposition


Input: Results show that the solidification features in the layer boundary were coarser than the layer core due to the recalescence mechanism.

solidification

mechanism

layer

layer

boundary

core


Input: Continuous eutectics were observed segregating the inter-dendritic regions in both the layer boundary and the layer core.

layer

layer

boundary

core


Input: The eutectics consisted of mainly Laves phase with a small amount of NbC precipitates.

Laves phase

precipitates


Input: Solidification front velocities (SFV) were calculated from the Kurz-Giovanola-Trivedi (KGT) model.

Solidification

model


Input: Results showed that they developed in the layer boundary and in the layer core at 0.06 m/s and 0.1 m/s respectively.

layer

layer

boundary

core


Input: Electron backscattered diffraction (EBSD) mapping revealed that small equiaxed grains nucleated in the layer boundary, while large columnar grains were prevalent in the layer core.

diffraction

EBSD

equiaxed grains

layer

layer

boundary

columnar grains

core


Input: The columnar to equiaxed transition (CET) model developed by Hunts was considered and the results were in good agreement with the observed grain morphologies.

transition

model

grain


Input: Metallization has been widely used to enhance the aesthetics and performance of injection molded plastic parts, but the techniques have not been widely extended to 3D printed parts due to intrinsic differences in surface chemistry and morphology.

Metallization

performance

surface

chemistry

morphology

plastic

3D printed parts


Input: Here, we investigate direct metallization of acrylonitrile butadiene styrene (ABS) 3D printed thermoplastic parts using low cost environmentally benign surface preparations and physical vapor deposition (PVD) to avoid the use of preparation with toxic chromic acid.

metallization

3D printed

surface preparations

physical vapor deposition

PVD

acrylonitrile butadiene styrene

ABS


Input: Fourier transform infrared (FTIR) spectra are gathered for each surface preparation method prior to metallization.

Fourier transform infrared

FTIR

surface preparation

metallization


Input: The metallized parts are then characterized for thin film adhesion, electrical resistivity, and optical reflectivity.

adhesion

electrical resistivity

optical


Input: Additionally, each part is imaged using a scanning electron microscope (SEM) post-metallization.

scanning electron microscope

SEM


Input: The results show that surface preparation with solvent results in a smooth and aesthetically pleasing surface, but metallic film adhesion is poor.

surface preparation

surface

metallic

adhesion


Input: Conversely, when 2000 grit sandpaper is used to mechanically prepare the surfaces, the resulting films have poor electrical conductivity and optical reflectance, but excellent adhesion.

sandpaper

surfaces

electrical conductivity

adhesion

optical


Input: Atmospheric plasma treatment of the parts results in the highest overall performance, with superior adhesion strength and optical reflectivity and low electrical resistivity.

plasma

performance

adhesion

optical

electrical resistivity


Input: Electron microscopy and FTIR reveal that the high adhesion resulting from atmospheric plasma is caused by modification surface morphology, but not surface chemical termination.

Electron microscopy

FTIR

surface morphology

adhesion

plasma

surface


Input: The results indicate that direct metallization of 3D printed ABS is a viable method for creating metallized parts with high performance and an aesthetically pleasing appearance and that the use of chromic acid in surface preparation is not necessary.

metallization

3D printed

surface preparation

performance


Input: The development and growth of additive manufacturing (AM) processes have made the optimization of surface quality and properties of AM components critical.

additive manufacturing

AM

AM

processes

optimization

properties

surface quality


Input: Laser polishing represents a recent and novel application of laser surface irradiation that can be used for precise, post-process smoothing of the rough surfaces commonly encountered on AM parts.

Laser

laser

irradiation

be

post-process

surfaces

AM parts


Input: Austenitic stainless steels are an important class of alloys frequently used in biomedical applications due to their corrosion resistance.

Austenitic stainless steels

alloys

biomedical applications

corrosion resistance


Input: Due to this, corrosion resistance advancements and improved bio-response to stainless steels are long-term active areas of research.

corrosion resistance

research

stainless steels

areas


Input: In this study, the influence of laser polishing on surface modification and corrosion behavior of additively manufactured 316L has been investigated.

laser

surface modification

additively manufactured

corrosion behavior


Input: Laser scanning speed and number of passes were varied to evaluate their effect on the surface quality and corrosion resistance of the experimental samples.

Laser

surface quality

corrosion resistance

experimental


Input: The results indicated that laser polishing could enable reductions in surface roughness of over 92% (from 4.75 μm to 0.49 μm Sa) while also incorporating partially melted powders originally on the as-printed surface layer.

laser

surface roughness

melted

surface

layer


Input: The X-ray diffraction (XRD) results indicated that there was no considerable phase change after laser polishing.

X-ray diffraction

XRD

phase

laser


Input: Laser polishing was observed to refine the columnar structure within the as-printed sample into a fine cellular structure.

Laser

structure

sample

cellular structure


Input: Additionally, the sub-surface microhardness of the laser remelted layer increased from 1.82 GPa to 2.89 GPa.

microhardness

laser

layer

GPa

GPa


Input: Moreover, the laser polished samples exhibited greater corrosion resistance, which was believed to be due to a combination of a decrease in surface roughness and grain refinement.

laser

samples

corrosion resistance

be

surface roughness

grain refinement


Input: These results show that laser polishing can improve the corrosion resistance of additive manufactured stainless steel while also decreasing surface roughness and increasing surface microhardness.

laser

corrosion resistance

surface

microhardness

additive manufactured

steel

surface roughness


Input: Due to those enhancements, it represents a suitable multifaceted process for finishing additive manufactured parts.

process

finishing

additive manufactured parts


Input: When it is difficult to deposit a material A on a material B, it is possible to create a Functionally Graded Material (FGM) using a buffer material between them to avoid the appearance of defects.

material

material

B

Functionally Graded Material

FGM

buffer

defects


Input: The literature shows that it is very difficult, nay impossible, to have an efficient metallurgical bond between Ti6Al4V and Inconel-Mo alloys without cracks, porosities or delamination.

metallurgical bond

delamination

alloys

porosities


Input: Moreover, the understanding of the phenomena taking place at the interface allows the preservation of the structural integrity of a FGM made by additive manufacturing.

interface

structural integrity

FGM

additive manufacturing


Input: CLAD® powder-based directed energy deposition allows the building of parts containing FGM and/or buffer materials directly during the process.

directed energy deposition

FGM

building of parts

buffer

process


Input: In this paper, the first interface 100 Ti6Al4V/25 Ti6Al4V–75 Mo (in wt%) is smooth, suggesting that there has been diffusion between both alloys.

interface

diffusion

Mo

alloys


Input: The second one, 25 Ti6Al4V–75 Mo/30 Inconel 718–70 Mo, contains numerous exotic structures between both alloys.

Mo

Inconel 718

Mo

alloys


Input: Thus, EDS, TKD and X-ray crystallography were performed right on this interface and revealed three main structures: a hexagonal matrix, a cubic structure and an ordered hexagonal one.

EDS

X-ray

crystallography

interface

hexagonal

cubic structure

hexagonal


Input: The hexagonal matrix appears to consist of Ni3Ti and the ordered hexagonal one of NiMo.

hexagonal

hexagonal


Input: Ultrasonic welding is a solid-state joining process which uses ultrasonic vibration to join materials at relatively low temperatures.

Ultrasonic welding

joining

solid-state

materials

ultrasonic vibration

temperatures


Input: Ultrasonic powder consolidation is a derivative of the ultrasonic additive process which consolidates powder material into a dense solid block without melting.

powder

additive

powder material

consolidation

melting


Input: During ultrasonic powder consolidation process, metal powder under a compressive load is subjected to transverse ultrasonic vibrations resulting in a fully-dense consolidated product.

powder

metal powder

consolidation

ultrasonic vibrations


Input: While ultrasonic powder consolidation process is employed in a wide variety of manufacturing processes, bonding mechanism of powder particles during the consolidation process is not clearly understood.

powder

powder particles

consolidation

consolidation

manufacturing processes

bonding mechanism


Input: This study uses a coupled thermo-mechanical finite element analysis technique to understand the underlying bonding mechanism involved in ultrasonic powder consolidation process.

thermo-mechanical

finite element analysis

consolidation

bonding mechanism

powder


Input: The study also investigates the effect of critical process parameters including vibrational amplitude and base temperature on the stress, strain, and particle temperature distribution during this process.

investigates

process parameters

particle

distribution

process

temperature

stress

strain


Input: Based on the results of the simulation, a possible theory on the bonding mechanism involved in ultrasonic powder consolidation process is proposed.

simulation

bonding mechanism

powder

consolidation


Input: The outcomes of this study can be used to further the industrial applications of ultrasonic powder consolidation process as well as other ultrasonic welding based processes.

be

powder

as

as

industrial

consolidation

processes

ultrasonic welding


Input: Additive Manufacturing (AM) has significantly increased the design freedom available for metal parts and provides significant flexibility within each build to produce multiple components of varying size and shape.

Additive Manufacturing

AM

design freedom

metal

flexibility

build

components


Input: In order to obtain the highest build efficiency, it is ideal to print multiple parts together spanning the entire plate with as little spacing as possible between the parts.

build

print

as

as


Input: Work has been performed to characterize the variance of materials properties as a function of location within the build volume as well as component density on the build plate.

materials

as

as

as

build volume

density

build plate


Input: This work utilizes mechanical, chemical, and microstructural analysis techniques to expand on previous work by statistically evaluating the impact of build location, and nearest neighbor proximity on tensile performance in Electron Beam Melted (EBM) Ti-6Al-4 V. Mechanical results are then correlated to structural phenomenon and the effectiveness of various strengthening mechanisms are determined.

mechanical

Mechanical

microstructural analysis

impact

performance

Electron Beam

correlated

effectiveness

strengthening mechanisms

build

tensile

EBM


Input: Results show that properties span a small range regardless of build design and that interstitial strengthening and lath spacing are the driving factors for mechanical strength.

properties

range

build

strengthening

mechanical strength


Input: Additive manufacturing (AM) technologies are used in three dimensional (3D) printing of parts using thermo-plastic extruders, or laser and electron beam based metal deposition methods.

Additive manufacturing

AM

technologies

electron beam

metal deposition

laser


Input: This paper presents an integrated methodology for planning of tangential path velocity, material deposition rate and temperature control of the extruded material which is deposited along curved paths.

methodology

planning

extruded

material

deposition rate

temperature


Input: The tangential velocity along the path is smoothed and optimized while respecting the heater’ s and extruder’ s capacities, as well as the feed drives’ jerk, acceleration and velocity limits.

s

s

as

as

extruder

feed

limits


Input: The extrusion rate is controlled proportional to the tangential path velocity while keeping the temperature of the deposited thermo-plastic material at the desired temperature by adaptively controlling current supply to the heater.

extrusion rate

temperature

temperature

material


Input: The experimentally proven algorithm leads to more uniform material deposition at sharp curvatures and resulting improved dimensional accuracy of printed parts.

algorithm

deposition

material

dimensional accuracy


Input: The proposed methodology can be extended to laser and electron beam based metal printing applications.

methodology

electron beam

be

metal

laser


Input: Directed energy deposition (DED) processes frequently rely on metallic powder and wire feedstock materials.

Directed energy deposition

DED

processes

metallic powder

wire feedstock materials