Input: This technique is demonstrated for the creation of multiple distinct conductive segments and to electroplate the same part with multiple metals to, for instance, allow a magnetic metal such as nickel and a highly conductive one such as copper to be incorporated in the same part.

metals

metal

as

as

be


Input: Following the characterization of the process, a representative 3D printed electrical device, a selectively electroplated solenoid inductor with low frequency inductance and resistance of 191 nH and 18.7 mΩ respectively was manufactured using this technique.

process

manufactured

3D printed

inductor

resistance


Input: This is a five order of magnitude reduction in resistance over the original value of 3 kΩ for the inductor before electroplating.

magnitude

resistance

inductor

electroplating


Input: Previous research on periodic lattice structures shows these structures are highly mechanically efficient with exceptionally high stiffness- and strength-to-weight ratios.

research

lattice structures


Input: Additive manufacturing technologies allow the construction slender member structures with complicated macroscale shapes.

Additive manufacturing

construction

macroscale


Input: Structures with large numbers of geometric objects cause the conventional methods for manipulating, storing, and slicing the geometry of these parts via STL files to be highly inefficient.

slicing

geometry

STL

files

be


Input: This work describes an alternate design process for slender member structures using efficient methods for manipulating, storing, and slicing the geometry of the part.

design process

slicing

geometry


Input: These new methods, in particular a fast, efficient direct slicing method, enable printing slender member structures with over one hundred thousand struts.

direct slicing

struts


Input: In this study, martensitic cold-work tool steel X65MoCrWV3-2 was processed by selective laser melting (SLM) by varying the laser scanning parameters and baseplate preheating temperatures.

tool

steel

processed

parameters

selective laser melting

SLM

preheating

laser


Input: Porosity as well as crack density of the SLM-densified steel were determined by quantitative image analysis.

Porosity

density

as

as

steel

quantitative

image analysis


Input: The resulting microstructure and the associated local mechanical properties were characterized, and the hardness-tempering behavior of the SLM-densified steel was compared to the behavior of the conventionally manufactured X65MoCrWV3-2 steel in the cast and hot-formed condition.

microstructure

mechanical properties

manufactured

steel

steel

cast


Input: Regardless of the preheating temperature, SLM-densified X65MoCrWV3-2 possesses a porosity of less than 0.5 vol.-%.

preheating

porosity


Input: The crack density was reduced significantly by means of a higher preheating temperature.

density

preheating


Input: The microstructure after SLM densification shows a fine, equiaxed cellular-dendritic subgrain structure, superimposed by lath- or needle-like martensite.

microstructure

structure

SLM

densification

martensite


Input: The martensite morphology appeared to be finer at a lower preheating temperature, whereas the observed subgrain structure did not seem to be influenced by the preheating temperatures.

martensite

be

be

preheating

preheating

structure


Input: Microhardness measurements indicated tempering effects in first solidified layers caused by the densification of subsequently deposited layers.

Microhardness

tempering

densification

deposited layers


Input: Peak hardness after tempering of the SLM-densified steel was found to be higher compared to the maximum hardness in the X65MoCrWV3-2 steel in the cast condition.

hardness

hardness

tempering

cast

steel

be

steel


Input: In order to ensure a reliable and repeatable additive manufacturing process, the material delivery rate in the directed energy deposition (DED) process requires in situ monitoring and control.

additive manufacturing process

directed energy deposition

DED

material

process

in situ


Input: This paper demonstrates acoustic emission (AE) sensing as a method of monitoring the flow of powder feedstock in a powder fed DED process.

acoustic emission

sensing

as

powder

powder feedstock

DED


Input: With minimal calibration, this signal closely correlates to the actual mass flow rate.

calibration

flow rate


Input: This article describes the fabricated mass flow monitoring system, documents various conditions in which the actual flow rate deviates from its set value, and details situations that highlight the system’ s utility.

fabricated

flow rate

set

s


Input: The work presented here highlights the results obtained and illustrates that accurate monitoring of powder flow in real-time regardless of environmental conditions within the build chamber is possible.

accurate

powder

build chamber


Input: Selective electron beam melting (SEBM) is a type of additive manufacturing (AM) that involves multiple physical processes.

Selective electron beam melting

SEBM

additive manufacturing

AM

physical processes


Input: Because of its unique process conditions compared to other AM processes, a detailed investigation into the molten pool behavior and dominant physics of SEBM is required.

process

molten pool

physics

AM processes

SEBM


Input: Fluid convection involves mass and heat transfer; therefore, fluid flow can have a profound effect on solidification conditions.

Fluid

heat transfer

solidification

fluid flow


Input: In this study, computational thermal-fluid dynamics simulations with multi-physical modeling and proof-of-concept experiments were used to analyze the molten pool behavior and resultant thermal conditions related to solidification.

simulations

modeling

molten pool

solidification


Input: The Marangoni effect of molten metal primarily determines fluid behavior and is a critical factor affecting the molten pool instability in SEBM of the Co–Cr–Mo alloy.

molten metal

fluid

alloy

critical factor

molten pool

SEBM


Input: The solidification parameters calculated from simulated data, especially the solidification rate, are sensitive to the local fluid flow at the solidification front.

solidification parameters

data

solidification

solidification rate

fluid flow


Input: Combined with experimental analysis, the results presented herein indicate that active fluid convection at the solidification front increase the probability of new grain formation, which suppresses the epitaxial growth of columnar grains.

experimental

solidification

probability

grain

fluid

epitaxial

columnar grains


Input: The capability of Additive Manufacturing (AM) to manufacture multi-materials allows the fabrication of complex and multifunctional objects with heterogeneous material compositions and varying mechanical properties.

Additive Manufacturing

AM

fabrication

manufacture

heterogeneous

mechanical properties


Input: The material jetting AM process specifically has the capability to manufacture multi-material structures with both rigid and flexible material properties.

material jetting AM process

manufacture

material properties


Input: Existing research has investigated the fatigue properties of 3D printed multi-material specimens and shows that there is a weakness at multi-material interfaces.

research

multi-material interfaces

fatigue

3D printed


Input: This paper seeks to, instead, investigate the effects of gradual material transitions on the fatigue life of 3D printed multi-material specimens.

material

fatigue life

3D printed


Input: In order to examine the fatigue life at the multi-material interface, stepwise gradients are compared against continuous gradients created through voxel-based design.

fatigue life

multi-material interface

design


Input: Results demonstrate the effects of different material gradient patterns and different material transition lengths on the fatigue life of multi-material specimens.

material gradient

multi-material

material

fatigue life


Input: In addition, the behavior of individual material composites is studied to confirm how gradient designs based on different material compositions affect their material properties.

material composites

material

designs

material properties


Input: The wire-based direct energy deposition of metallic lightweight materials such as titanium or aluminium alloys has recently received increasing attention in industry and academia.

direct energy deposition

metallic

as

aluminium alloys

lightweight

industry


Input: However, high-throughput deposition is mostly associated with process-limiting phenomena such as the development of high temperatures resulting in poor surface quality as well as coarse and unidirectional solidification microstructures.

deposition

unidirectional solidification

as

as

as

microstructures

temperatures

surface quality


Input: In this regard, laser systems, which are already widely used in industrial processes, allow for a great variety in the controllability of energy inputs, thereby enabling the control of process temperatures and resulting microstructures.

laser

industrial

process

microstructures


Input: The subject of the current study is the detailed elucidation and evaluation of important features such as the development of temperature gradients, resulting cooling rates and thermal cycles for different laser beam irradiances.

as

temperature gradients

cooling rates

thermal cycles

laser beam


Input: Significant heat accumulation and process instabilities as well as inhomogeneous thermal profiles along the length and height of the parts were observed at a high laser beam irradiance.

heat accumulation

process

thermal profiles

laser beam

as

as


Input: In contrast, lower laser beam irradiance resulted in a more stable process with increased cooling rates, which favourably influenced the refinement of the solidification microstructure.

laser beam

process

solidification microstructure

cooling rates


Input: Selective Laser Sintering (SLS) is a rapidly growing additive manufacturing process, because it has the capacity to build parts from a variety of materials.

Selective Laser Sintering

SLS

additive manufacturing process

capacity

materials

build


Input: However, the dimensional accuracy of the fabricated parts in this process is dependent on the ability to control phenomena such as warpage and shrinkage.

dimensional accuracy

fabricated

process

shrinkage

as


Input: This research presents an optimization algorithm to find the best processing parameters for minimizing warpage.

research

optimization algorithm

parameters

warpage


Input: The finite element method was used to simulate the sintering of a layer of polymer powder, and the warpage of the layer was calculated.

finite element method

warpage

sintering

layer

layer

polymer


Input: The numerical model was verified through comparison with experimental results.

model

experimental


Input: A back-propagation neural network was used to formulate the mapping between the design variables and the objective function.

neural network

design


Input: Results of 40 simulation cases with various input parameters such as scanning pattern and speed, laser power, surrounding temperature, and layer thickness were used to train and test the neutral network.

simulation

parameters

pattern

as

laser power

temperature

layer thickness


Input: Finally, The Genetic Algorithm was employed to optimize the objective function, and the influence of parameters on warpage was investigated.

Genetic Algorithm

parameters

warpage


Input: Insight into the performance of fibre-reinforced functionally graded lattices (FGLs) from an experimental perspective.

performance

experimental

functionally graded lattices


Input: Effect of grading severity and build direction on the stiffness, energy absorption and structural response of FGLs.

build direction

stiffness

energy absorption


Input: Categorization of FGLs with regards to ideally bending/stretching-dominated lattices, as proposed by Gibson-Ashby model.

lattices

Gibson-Ashby model

as


Input: Semi-empirical analysis of the energy absorption and stiffness estimation for higher fibre volume fraction (Halpin-Tsai).

energy absorption

stiffness

fibre

fraction


Input: the scope for fine-tuning the properties of lattices to harness the potential for multi-functional AM-parts.

properties

lattices


Input: Architectured structures, particularly functionally graded lattices, are receiving much attention in both industry and academia as they facilitate the customization of the structural response and harness the potential for multi-functional applications.

functionally graded lattices

industry

as


Input: This work experimentally investigates how the severity of density and unit cell size grading as well as the building direction affects the stiffness, energy absorption and structural response of additively manufactured (AM) short fibre-reinforced lattices with same relative density.

investigates

unit cell

lattices

density

stiffness

relative density

as

as

building direction

energy absorption

additively manufactured

AM


Input: Specimens composed of tessellated body-centred cubic (BCC), Schwarz-P (SP) and Gyroid (GY) unit cells were tested under compression.

BCC

unit cells

compression


Input: Compared to the uniform lattices of equal density, it was found, that modest density grading has a positive and no effect on the total compressive stiffness of SP and BCC lattices, respectively.

lattices

BCC

density

density

stiffness


Input: Unit cell size grading had no significant influence on the stiffness and revealed an elastomer-like performance as opposed to the density graded lattices of the same relative density, suggesting a foam-like behaviour.

Unit cell

performance

lattices

stiffness

density

relative density

as


Input: Density grading of bending-dominated unit cell lattices showcased better energy absorption capability for small displacements, whereas grading of the stretching-dominated counterparts is advantageous for large displacements when compared to the ungraded lattice.

Density

unit cell

lattices

energy absorption

ungraded lattice


Input: The severity of unit cell size graded lattices does not affect the energy absorption capability.

unit cell

lattices

energy absorption


Input: Finally, a power-law approach was used to semi-empirically derive a formula that predicts the cumulative energy absorption as a function of the density gradient and relative density.

energy absorption

as

density gradient

relative density


Input: The microstructure and mechanical properties of lattice structures of various relative densities manufactured by Electron Beam Melting were analyzed.

microstructure

mechanical properties

manufactured

lattice structures

relative densities

Electron Beam Melting


Input: Special interest was given to the effect of surface roughness on their elastic behavior.

surface roughness

elastic


Input: Compression testing revealed that the important decrease in roughness caused by chemical etching results in an increase in relative stiffness, in comparison with an as-built structure of the same relative density.

Compression

roughness

stiffness

relative density

etching

structure


Input: This study investigates the material and mechanical properties of both polyamide 12 (PA12) and reinforced glass bead PA12 composites, fabricated using a production scale additive manufacturing (AM) process.

investigates

mechanical properties

reinforced

fabricated

process

material

polyamide 12

glass bead

composites

production

additive manufacturing

AM


Input: The printing studies were carried out using the production scale, Multi Jet Fusion powder bed fusion process.

production

Multi Jet Fusion

bed fusion


Input: The study demonstrated that the chemical functionality and the thermal properties of the printed PA 12 parts and the glass bead composite, were similar.

thermal properties

PA

glass bead

composite


Input: Based on DSC measurements, the melting temperature was 184 °C and 186 °C and the associated cooling cycle temperature was 150 °C and 146 °C for the composite and the PA12 respectively.

DSC

melting temperature

temperature

cooling

composite


Input: The percentage crystallinity of the glass bead composite was 24%, compared with the 31% obtained for the PA12 only parts.

glass bead

composite


Input: Based on mechanical tests, the addition of glass beads increased the tensile and flexural modulus by 85% and 36% and lowered the tensile and flexural strength by 39% and 15% respectively.

mechanical tests

glass beads

tensile

tensile

flexural strength


Input: The effect of print orientation during the MJF process was evaluated based on porosity and mechanical performance.

print

MJF

orientation

porosity

mechanical


Input: Using X-ray micro computed tomography, it was demonstrated that the porosity of the PA12 and composite parts were less than 1%.

X-ray micro computed tomography

porosity

composite


Input: Polymer and composite parts printed in the ZYX orientation were found to exhibit both the lowest porosity and highest mechanical strengths.

Polymer

composite

orientation

porosity

mechanical strengths


Input: The spatiotemporal variations of the molten pool and deposit profiles during laser Directed Energy Deposition (DED) largely affect the formation of printing defects and the build quality.

variations

molten pool

defects

profiles

laser Directed Energy Deposition

DED

build


Input: Quantitative assessment of the dependencies of molten pool characteristics on critical process variables is helpful to reveal the evolution of the depositing tracks.

Quantitative assessment

molten pool

process

evolution


Input: To this end, a novel 3D transient phenomenological model was developed in this work to explore the evolution of the temperature and velocity fields and the molten pool dimensions for both single-track and multi-track laser DED deposits.

phenomenological model

evolution

molten pool

temperature

dimensions

laser

DED


Input: The computed deposit profiles showed that the contact angles of the single-tracks increased significantly with higher MUL intensity.

profiles

contact


Input: The simulation results showed that convex deposit profiles obtained at high MUL intensity further caused inter-track voids during multi-track deposition.

simulation

profiles

voids

deposition


Input: To compare the effect of selective laser melting variables on different mechanical properties and compare the results.

selective laser melting

mechanical properties


Input: Statistical analysis was used for characterising the interaction and effect of parameters on the hardness and density.

parameters

hardness

density


Input: Describing the governing phenomena on melting pool rheology and its effect on density and hardness.

melting

rheology

density

hardness


Input: In this paper, we printed Ti-6Al-4V SLM parts based on Taguchi design of experiment and related standards to measure and compare hardness with different mechanical properties that were obtained in our previous research such as density, strength, elongation, and average surface.

as

SLM

design of experiment

standards

mechanical properties

research

average

hardness

strength

elongation


Input: Then the effect of process parameters comprising laser power, scan speed, hatch space, laser pattern angle coupling, along with heat treatment as a post-process, in relation to hardness was analysed.

process parameters

post-process

laser power

scan speed

laser

heat treatment

as

hardness


Input: Another contribution is related to the analysis of process parameters in relation to hardness and explaining them by rheological phenomena.

process parameters

hardness

rheological


Input: The results showed an interesting similarity between hardness and density which is highly related to the formation of the melting pool and porosities within the process.

hardness

density

porosities

melting

process


Input: The layerwise production paradigm entailed in laser powder bed fusion (LPBF) offers the opportunity to acquire a wide range of information about the process stability and the part quality while the part is being manufactured.

production

laser powder bed fusion

LPBF

range

process

quality

manufactured


Input: Different authors pointed out that high-resolution imaging of each printed layer combined with image segmentation methods can be used to detect powder recoating errors together with surface and geometrical defects.

high-resolution

layer

image

errors

surface

defects

be

powder


Input: The paper presents the first study aimed at characterizing the accuracy of in-situ contour identification in LPBF layerwise images by means of a measurement system performance characterization.

accuracy

measurement

in-situ contour

images

performance

LPBF


Input: Different active contours segmentation methods are compared, and the sources of variability of the resulting measurements are investigated in terms of repeatability, part-to-part and build-to-build variability.

contours

variability

repeatability

variability


Input: The study also analyses and compares the sensitivity of in-situ measurements to different lighting conditions and laser scan directions.

sensitivity

in-situ

laser scan


Input: The results show that, by combining appropriate image pre-processing and segmentation algorithms with suitable lighting configurations, a high measurement repeatability can be achieved, i.e., a pure error that is up to one order of magnitude lower than the total measurement variability.

image

algorithms

error

measurement

measurement

be

magnitude


Input: This performance enables the detection of major geometric deviations and it paves the way to the design of statistical in-situ quality monitoring tools that rely on layerwise image segmentation.

performance

in-situ

image

design

tools


Input: Previous studies have shown that 3D printed composites exhibit an orthotropic nature with inherently lower interlayer mechanical properties.

3D printed

orthotropic

mechanical properties


Input: This research work is an attempt to improve the interlayer tensile strength of extrusion-based 3D printed composites.

research

tensile strength

3D printed


Input: Annealing was identified as a suitable post-processing method and was the focus of this study.

Annealing

as

post-processing


Input: Two distinct thermoplastic polymers, which are common in 3D printing, were selected to study the enhancement of interlayer tensile strength of composites by additive manufacturing: a) an amorphous polyethylene terephthalate-glycol (PETG), and b) a semi-crystalline poly (lactic acid) (PLA).

thermoplastic polymers

composites

polyethylene

b

PLA

3D printing

additive manufacturing

tensile strength


Input: It was determined that short carbon fiber reinforced composites have lower interlayer tensile strength than the corresponding neat polymers in 3D printed parts.

short carbon fiber

composites

polymers

reinforced

tensile strength

3D printed parts


Input: This reduction in mechanical performance was attributable to an increase in melt viscosity and the consequential slower interlayer diffusion bonding.

reduction

melt

diffusion bonding

mechanical


Input: However, the reduction in interlayer tensile strength could be recovered by post-processing when the annealing temperature was higher than the glass transition temperature of the amorphous polymer.

reduction

post-processing

glass transition temperature

tensile strength

be

polymer

annealing


Input: In the case of the semi-crystalline polymer, the recovery of the interlayer tensile strength was only observed when the annealing temperature was higher than the glass transition temperature but lower than the cold-crystallization temperature.

polymer

tensile strength

annealing

glass transition temperature

temperature


Input: This study utilized rheological and thermal analysis of 3D printed composites to provide a better understanding of the interlayer strength response and, therefore, overcome a mechanical performance limitation of these materials.

rheological

thermal analysis

3D printed

interlayer strength

materials

mechanical


Input: In situ high-speed thermal monitoring of melt-pool during laser powder bed fusion.

In situ

laser powder bed fusion


Input: Probabilistic prediction of pore formation based on in situ pyrometry monitoring.

prediction

in situ

pore


Input: Detection of conduction-to-keyhole transition using high-speed pyrometry.

transition

pyrometry


Input: Creation of pores and defects during laser powder bed fusion (LPBF) can lead to poor mechanical properties and thus must be minimized.

pores

defects

mechanical properties

laser powder bed fusion

LPBF

lead

be


Input: Post-build inspection is required to ensure the printed parts contain acceptably low defect concentrations.

inspection

defect


Input: As a potential solution, in situ process monitoring can be used to detect the creation of defects, characterize local material behavior and predict expected component properties.

As

be

material

solution

in situ

defects

component


Input: However, the precise relationship between pore creation and in situ process monitoring still needs to be understood.

pore

in situ

be


Input: In this work, high-speed infrared diode-based pyrometry and high-speed optical imaging signals were used to monitor LPBF printing of 446 stainless steel 316 L single tracks with varying laser power and velocity.

infrared

monitor

pyrometry

optical

imaging

LPBF

stainless steel

laser power


Input: Results indicate an increase in pyrometer signal and melt pool dimensions with increasing laser power and decreasing velocity in agreement with previous work.

melt pool dimensions

laser power


Input: Critically, pore defect initiation as characterized by ex situ X-ray radiography was correlated with in situ thermal monitoring signals to derive the probability of defect creation.

pore

defect

correlated

in situ

probability

defect

as

X-ray

radiography


Input: Our results show that, in principle, a probabilistic prediction of pore formation can be achieved based on in situ high-speed pyrometry monitoring of the LPBF melt pool.

prediction

in situ

pore

be

pyrometry

LPBF


Input: Selective laser melting (SLM) is an attractive technology, enabling the manufacture of customised, complex metallic designs, with minimal wastage.

Selective laser melting

SLM

technology

manufacture

metallic

designs


Input: However, uptake by industry is currently impeded by several technical barriers, such as the control of residual stress, which have a detrimental effect on the manufacturability and integrity of a component.

industry

as

residual stress

manufacturability

integrity

component


Input: Indirectly, these impose severe design restrictions and reduce the reliability of components, driving up costs.

design

reliability

components


Input: This paper uses a thermo-mechanical model to better understand the effect of laser scan strategy on the generation of residual stress in SLM.

thermo-mechanical model

laser scan

residual stress

SLM


Input: A complex interaction between transient thermal history and the build-up of residual stress has been observed in the two laser scan strategies investigated.

transient

residual stress

laser scan


Input: The temperature gradient mechanism was discovered for the creation of residual stress.

temperature gradient mechanism

residual stress


Input: The greatest stress component was found to develop parallel to the scan vectors, creating an anisotropic stress distribution in the part.

stress

anisotropic

component

distribution


Input: The stress distribution varied between laser scan strategies and the cause has been determined by observing the thermal history during scanning.

stress distribution

laser scan

scanning


Input: Using this, proposals are suggested for designing laser scan strategies used in SLM.

laser scan

SLM


Input: Near-net shape metal parts of great geometrical complexity are fabricated by the Laser Powder Bed Fusion (L-PBF) technology directly from a CAD model.

metal

geometrical complexity

fabricated

technology

Laser Powder Bed Fusion

L-PBF

CAD model


Input: Therefore, parts can be lightweight, less expensive in terms of material use and with shapes that may be impossible to produce by conventional technology.

be

material

be

technology


Input: The fatigue behavior of L-PBF part in as-built condition is negatively affected by poor surface quality.

fatigue

L-PBF

surface quality


Input: Surface finishing after fabrication may be either unacceptably costly or impossible because the surface is inaccessible.

Surface finishing

fabrication

be

surface


Input: Fatigue performance can be further reduced by the notch effect due to local geometrical variations.

Fatigue

be

notch

variations


Input: Among the Al-alloys, AlSi10Mg is readily processed with L-PBF and it is of interest for different industrial sectors.In this contribution two aspects, that is: i) the directional smooth fatigue behavior of as-built AlSi10Mg, and ii) the notch fatigue behavior with as-built surfaces are investigated.

processed

surfaces

L-PBF

industrial

fatigue

fatigue

notch


Input: Eight sets of un-notched and notched miniature specimens of AlSi10Mg were produced as a single batch by L-PBF and tested in the as-build state under cyclic plane bending loading.

as

L-PBF

bending


Input: The smooth fatigue behavior was determined as very sensitive to applied stress direction with respect to the build direction.

fatigue

stress

as

build direction


Input: The directional nature of the fatigue behavior was confirmed by notch fatigue data.

fatigue

fatigue

notch

data


Input: Therefore, four notch fatigue factors that depend on the PBF technology were introduced and determined.

notch

fatigue

PBF


Input: The fatigue behavior of L-PBF AlSi10Mg obtained here was compared satisfactorily against recent data obtained with standard specimen geometries and test methods.

fatigue

L-PBF

data

standard

geometries


Input: The present methodology using mini specimens under cyclic bending efficiently determines the fatigue response of L-PBF metals.

methodology

bending

L-PBF

fatigue


Input: Interlayer bonds pose regions of weakness in structures produced via melt extrusion based polymer additive manufacturing.

melt extrusion

polymer additive manufacturing


Input: Bond strength was assessed both between layers and within layers as a function of print parameters by performing tensile tests on ABS coupons printed in two orientations.

Bond strength

parameters

orientations

as

ABS

print

tensile tests


Input: Print parameters considered were extruder temperature, print speed, and layer height.

Print

print

parameters

extruder

layer height


Input: An IR camera was used to track thermal history of interlayer bond lines during the printing process.

IR

camera

printing process


Input: Contact length between roads was measured from mesostructure optical micrographs.

Contact

optical


Input: Print speed was found to have a large impact on tensile strength with high speeds generally yielding lower strength.

Print

impact

tensile strength

strength


Input: A plateau in tensile strength of 22 MPa was observed for a normalized contact length greater than 0.6 independent of print orientation.

tensile strength

MPa

orientation

contact

print


Input: Laser powder bed fusion (LPBF) is a popular additive manufacturing (AM) process that has shown promise in fabricating novel components that can be utilized for a wide variety of applications.

Laser powder bed fusion

LPBF

additive manufacturing

AM

fabricating

process

components

be


Input: However, one of the main drawbacks of LPBF is that it produces large thermal gradients and fast cooling rates during the solidification of each layer, which can lead to large levels of residual stress/distortion, sometimes resulting in build failure/rejection.

LPBF

thermal gradients

cooling rates

layer

build

solidification

residual

lead


Input: In the present work, several experimental techniques (x-ray diffraction, hole drilling, contour method, and laser line profilometry) were utilized to establish the effect of LPBF process parameters (scan speed, laser power, build height, build plan area, and substrate condition) on residual stress evolution and distortion.

experimental

parameters

evolution

distortion

x-ray diffraction

hole drilling

LPBF

contour

laser

scan speed

laser power

build height

build

area

substrate

residual stress


Input: X-ray diffraction and hole-drilling measurements were performed on the surfaces of the LPBF deposits and substrates, while bulk residual stresses were measured using the contour method.

X-ray diffraction

surfaces

LPBF

residual stresses

contour


Input: In addition, a laser line profilometer was used to measure the distortion after fabrication.

laser

profilometer

distortion

fabrication


Input: The results obtained by the non-destructive and destructive measurement techniques suggested that process parameters greatly influence the development of residual stress and distortion throughout the LPBF deposit and the substrate.

measurement

process parameters

distortion

residual stress

LPBF

substrate


Input: Furthermore, the experimental results in this work provide a valuable foundation for future modeling and simulation of the evolution of residual stress and distortion.

experimental

evolution

distortion

modeling

simulation

residual stress


Input: Selective laser melting (SLM) is a method of laser powder bed fusion additive manufacturing (AM) currently being pursued in numerous industries, including space launch and space flight.

Selective laser melting

SLM

laser powder bed fusion additive manufacturing

AM

industries


Input: In this study we performed an extensive parameter development investigation to better understand the effect of laser parameters on surface roughness, density, and porosity of SLM Inconel 718 parts.

parameter

laser

surface roughness

density

porosity

SLM

Inconel 718


Input: Laser energy density was varied via laser focus shift, and the effects on porosity in both as-printed and post-HIP treated states were analyzed.

Laser energy density

laser

porosity


Input: Tensile testing was also conducted to investigate the effect of processing conditions on the mechanical properties of SLM 718.

Tensile testing

mechanical properties

SLM


Input: It was found that for these laser parameters, while the material met ultimate tensile strength and yield strength requirements per AMS 5662, the strain-to-failure was reduced with negative focus shift due to increases in porosity levels.

laser

material

ultimate tensile strength

yield strength

porosity


Input: It was also found that while correlations were observed between surface roughness, density, and porosity within the laser focus shift range investigated, porosity measurement appears to be the clearest indicator of build quality for AM processed 718.

surface roughness

density

porosity

porosity

laser

range

build

measurement

be

AM


Input: Managing the dimensional accuracy of parts produced by the Electron Beam Melting process is a challenge.

dimensional accuracy

Electron Beam Melting


Input: For small dimensions, as in lattice structures (strut diameters), accuracy becomes even more important and geometric quality is linked to mechanical properties.

dimensions

lattice structures

as

strut diameters

accuracy

quality

mechanical properties


Input: The dimensional quality of parts produced by EBM can be influenced by many process parameters.

quality

process parameters

EBM

be


Input: Simulating the process can help the machine user to choose the best process parameters and improve build dimensional accuracy.

process

process parameters

machine

build

accuracy


Input: The work presented here is based on a method for linking process parameters with beam parameters.

process parameters

beam


Input: Once linked, both sets of parameters are then integrated into a full simulation of the process in order to make trajectory optimization possible.

parameters

process

optimization

simulation


Input: First, this paper explains how the finite element model described in the literature can be improved to simulate the multilayer EBM process.

finite element model

be

EBM


Input: It then describes how this simulation is used to develop a method to characterize the machine beam and determine the link between the focus current and the beam diameter.

simulation

machine

beam

beam diameter


Input: Finally, it shows how this simulation can be applied to a built shape (vertical strut) hence demonstrating improved accuracy of the produced part.

simulation

be

vertical

strut

accuracy


Input: Additive manufacturing (AM) is a rapidly expanding framework of production technologies evolving in different directions, following the needs of different industries.

Additive manufacturing

AM

production

framework

industries


Input: Among powder bed fusion technologies, one of the main branches of AM, selective laser sintering (SLS) is the second oldest one.

powder bed fusion

AM

selective laser sintering

SLS


Input: In the last few years, a direct rival has emerged: multi jet fusion (MJF).

multi jet fusion

MJF


Input: The purpose of this work is to compare these processes throughout a systematic analysis of powder and final parts made of commercially available polyamide 12 (PA12).

processes

powder

polyamide 12


Input: Differences have been spotted both on the molecular and powder scale, with end capping of the MJF feedstock together with different thermal properties of the new and recycled materials.

powder

feedstock

MJF

thermal properties

recycled materials


Input: On the other hand, flowing properties are similar among the two virgin and recycled powders, with only a significant change in the fraction of fines for SLS material.

properties

recycled

fraction

powders

material

SLS


Input: The parts produced through SLS exhibit higher Young's modulus but lower elongation at break and ultimate tensile strength if compared to the ones obtained using MJF.

SLS

MJF

elongation

ultimate tensile strength


Input: Also Charpy impact strength according to ISO 179 has been tested, confirming the literature data for SLS, but also showing higher strength in the out-of-plane direction for un-notched specimens coming from MJF.

impact

data

ISO

SLS

MJF

strength


Input: Finally, the evaluation of advanced area roughness parameters such as surface roughness, skewness and kurtosis according to ISO 25178 allows the ascertainment of subtle differences arising in parts with different positioning on the build platform, possibly due to the inks employed in the MJF process.

area

parameters

as

roughness

ISO

build platform

MJF


Input: An effective process prediction model was developed for additive manufacturing.

process prediction

model

additive manufacturing


Input: High entropy alloy was used to test the model.

alloy

model


Input: The model effectively predicts energy density for processing metallic materials.

model

energy density

metallic materials


Input: Surface structure of power and powder bed can improve laser absorptivity.

Surface structure

power

powder bed

laser


Input: Selective laser melting (SLM) is a laser-based additive manufacturing technique that can fabricate parts with complex geometries and sufficient mechanical properties.

Selective laser melting

SLM

laser-based additive manufacturing

fabricate

complex geometries

mechanical properties


Input: However, the optimal SLM process windows of metallic materials are difficult to predict, especially when exploring new metallic materials.

SLM

process

metallic materials

metallic materials


Input: In this paper, a universal and simplified model has been proposed to predict the energy density suitable for SLM of a variety of metallic materials including Ti and Ti alloys, Al alloy, Ni-based superalloy and steel, on the basis of the relationship between energy absorption and consumption during SLM.

model

energy density

SLM

SLM

metallic materials

Ti

Ti alloys

Al alloy

steel

energy absorption


Input: Several important but easily overlooked factors, including the surface structure of metallic powder, porosity of powder bed, vaporization and heat loss, were considered to improve the accuracy of the model.

surface structure

metallic powder

porosity

powder bed

heat

model

accuracy


Input: Results show that, to achieve near-full density parts, the energy absorption (Qa) by the local powder bed should be approximately 3–8 times greater than the energy consumption (Qc), and this finding applies to all materials investigated.

density

energy absorption

powder bed

be

materials


Input: The value of Qa/Qc highly depends on material properties, particularly laser absorptivity, latent heat of melting and specific heat capacity.

material properties

heat

capacity

laser

melting

specific heat


Input: Experiments on high-entropy alloy (CrMnFeCoNi) and Hastelloy X alloy, new metallic materials for SLM, have been further conducted to verify the model.

alloy

Hastelloy

alloy

metallic materials

SLM

model


Input: Results confirm that the model can predict suitable laser energy densities needed for processing the various metallic materials without tedious trial and error experiments.

model

trial and error

laser energy densities

metallic materials


Input: Therefore, medical additive manufacturing techniques are developed for fabrication of such implants, but currently do not achieve the required printing resolution.

medical

implants

additive manufacturing

fabrication

resolution


Input: This is caused by intensive droplet spreading of the initially liquid silicone rubber on the printing substrate.

droplet

silicone rubber

substrate


Input: While empirical optimization approaches for the droplet spreading are intensive in cost and time, we develop a mathematical optimization approach to calculate the optimal printing parameters for minimal droplet spreading.

empirical

droplet

mathematical

parameters

droplet


Input: Since the viscosity profile of thermal curing silicone rubber is the main reason for the droplet spreading, we implemented a rheology model for calculation of the optimal heat curing parameters.

viscosity

rheology

profile

curing

rubber

droplet

model

heat curing


Input: A Dual-Arrhenius equation was used to correlate the temperature-time-profile of the curing process with the curing-related viscosity rise and the temperature-related viscosity fall of the liquid silicone rubber.

curing

viscosity

viscosity

silicone rubber


Input: Two commonly used silicone rubbers were characterized with a rheometer at different isothermal and anisothermal curing profiles.

silicone rubbers

isothermal

curing


Input: High correlation between the calculated and the measured viscosity profiles were observed, giving the ability to optimize the curing process parameters to the rheological behaviour of the used silicone rubber.

viscosity

rheological

profiles

curing

parameters

silicone rubber


Input: Powder bed fusion (PBF) is ideally suited to build complex and near-net-shaped metallic structures such as conformal cooling channel networks in injection molds.

Powder bed fusion

PBF

build

metallic structures

cooling channel

molds

as


Input: However, warpage occurring due to the residual stresses inherent to this process can lead to shape deviation in the internal channels and needs to be minimized.

warpage

process

residual stresses

lead

be


Input: In this research, a novel analytical model based on the Euler-Bernoulli beam bending theory was developed to estimate the residual stress-induced deformation of internal channels printed horizontally using PBF.

research

model

residual

deformation

beam

PBF


Input: The proposed approach is thus expected to be a useful tool to generate design-for-AM guidelines for the additive manufacturing of overhangs and internal channels.

be

tool

additive manufacturing

overhangs


Input: Risk-averse areas such as the medical, aerospace and energy sectors have been somewhat slow towards accepting and applying Additive Manufacturing (AM) in many of their value chains.

areas

as

medical

aerospace

Additive Manufacturing

AM


Input: This is partly because there are still significant uncertainties concerning the quality of AM builds.This paper introduces a machine learning algorithm for the automatic detection of faults in AM products.

quality

AM

AM

machine learning algorithm


Input: The approach is semi-supervised in that, during training, it is able to use data from both builds where the resulting components were certified and builds where the quality of the resulting components is unknown.

data

quality

builds

builds

components

components


Input: This makes the approach cost efficient, particularly in scenarios where part certification is costly and time consuming.The study specifically analyses Laser Powder-Bed Fusion (L-PBF) builds.

Laser

Fusion

L-PBF

builds


Input: Key features are extracted from large sets of photodiode data, obtained during the building of 49 tensile test bars.

extracted

data

tensile test


Input: Ultimate tensile strength (UTS) tests were then used to categorise each bar as ‘faulty’ or ‘acceptable’.

Ultimate tensile strength

UTS

as


Input: As Additive Manufacturing (AM) adoption grows, the demand for improved quality output product is increasing.

As

Additive Manufacturing

AM

quality


Input: This is evident in the desire for both increased repeatability and higher strength and ductility in Selective Laser Sintered (SLS®) Polymer parts.

repeatability

strength

ductility

Selective Laser

Polymer


Input: One approach to expanding the performance envelope for polymers in this domain is through high temperature manufacturing processes, supporting the use of polymers with increased mechanical strength, lighter weight, and a favorable ability to sterilize for medical applications.

performance

domain

polymers

polymers

temperature

weight

manufacturing processes

mechanical strength

medical applications


Input: Early candidate materials that exhibit higher melting and glass transition temperatures include the Poly Ether Ether Ketone (PEEK) and Polyaryletherketone (PAEK) family of materials.

materials

glass transition temperatures

materials

melting

PEEK


Input: This paper describes the design of a laboratory SLS® machine for operation with these and other similar materials, emphasizing its thermal and operational design features.

design

design

laboratory

materials

machine


Input: Data is also provided from initial testing of key subsystems during assembly and prior to full system operation.

Data

testing

assembly


Input: Because this machine is intended to explore processing new materials, it also incorporates features for improving the data collection, and associated feedback control for improved repeatability, and ultimately defect detection and mitigation during the Additive Manufacturing.

machine

materials

data

repeatability

defect

feedback

Additive Manufacturing


Input: One of the major challenges with the powder bed fusion process (PBF) and formation of bulk metallic glass (BMG) is the development of process parameters for a stable process and a defect-free component.

powder bed fusion process

PBF

metallic glass

process parameters

process

component


Input: The focus of this study is to predict formation of a crystalline phase in the glass forming alloy AMZ4 during PBF.

phase

glass forming

PBF

alloy


Input: The approach combines a thermal finite element model for prediction of the temperature field and a phase model for prediction of crystallization and devitrification.

finite element model

prediction

phase model

prediction

crystallization

temperature

devitrification


Input: The challenge to simulate the complexity of the heat source has been addressed by utilizing temporal reduction in a layer-by-layer fashion by a simplified heat source model.

complexity

heat source

reduction

layer-by-layer fashion

heat source


Input: The heat source model considers the laser power, penetration depth and hatch spacing and is represented by a volumetric heat density equation in one dimension.

heat source

heat

laser power

penetration depth

hatch spacing

density

dimension


Input: The phase model is developed and calibrated to DSC measurements at varying heating rates.

phase model

calibrated

DSC

heating


Input: It can predict the formation of crystalline phase during the non-isothermal process.

phase

process


Input: Results indicate that a critical location for devitrification is located a few layers beneath the top surface.

devitrification

surface


Input: Nickel aluminium bronze (NAB) is widely used in naval applications due to its combination of excellent corrosion resistance in sea water applications and medium strength levels.

Nickel aluminium

bronze

NAB

naval applications

corrosion resistance

strength


Input: These alloys have complex microstructures of α and β solid solution phases together with different forms of the intermetallic κ phase.

alloys

microstructures

solid solution

intermetallic

phase


Input: In this work, selective laser melting (SLM) of Cu-9.8Al-5.2Ni-4.6Fe-0.3 Mn (wt.

selective laser melting

SLM

Mn


Input: %) NAB powder was optimised to produce dense NAB specimens.

NAB

NAB


Input: The as-built specimens consisted of martensitic microstructures.

microstructures


Input: Through the application of various heat treatment conditions, α + κ microstructures typical of traditional NAB alloys, were obtained and the mechanical and electrochemical properties were characterized.

heat treatment

microstructures

NAB

alloys

mechanical

electrochemical


Input: A heat treatment at 700 °C for 1 h on the as-built structure yielded NAB specimens with superior corrosion performance and mechanical properties than conventional wrought or cast NAB.

heat treatment

cast

structure

corrosion

mechanical properties

wrought

NAB


Input: This work shows that SLM of NAB alloys is possible and the components obtained exhibit properties at least as good as their cast or wrought counterparts.

SLM

cast

NAB

alloys

as

as

components

properties

wrought


Input: This opens up the possibility of using NAB components fabricated by SLM in engineering applications.

NAB

components

SLM

engineering


Input: Two batches of pre-alloyed Hastelloy-X powder with different Si, Mn and C contents were used to produce specimens by Selective Laser Melting (SLM).

powder

Si

Mn

C

Selective Laser Melting

SLM


Input: Two major reasons that control crack formation and propagation were considered: (i) internal strain accumulation due to the thermal cycling that is characteristic to SLM processing; (ii) crack formation and propagation during solidification.

strain

thermal cycling

SLM

solidification


Input: This phenomenon, known as hot tearing, is frequently found in conventional casting and is dependent on chemical composition.

as

casting

chemical composition


Input: Using thermodynamic software simulation, the temperature vs fraction of solid curves was used to determine hot tearing sensitivity as a function of Si, Mn and C content.

software

fraction

simulation

temperature

sensitivity

as

Si

Mn

C


Input: It was found that low Si and C contents help in avoiding crack formation whereas cracking propensity was relatively independent of Mn concentration.

Si

C

Mn

cracking


Input: Hence, the cracking mechanism during SLM is believed to be as follows: crack initiation is mainly induced during solidification and is dependent on the content of minor alloying elements such as Si and C, whereas crack propagation predominantly occurs during thermal cycling.

cracking

solidification

crack propagation

SLM

be

as

alloying elements

as

C

thermal cycling


Input: If microstructures free of micro-cracks after solidification can be generated with optimised SLM parameters, these manufactured parts can sustain the internal strain level and, thus, crack formation and propagation can be avoided.

microstructures

be

be

micro-cracks

solidification

parameters

manufactured

SLM

strain


Input: Laser spatter is coarser and more spherical than virgin powder.

Laser

spherical

virgin powder


Input: Condensate condenses on the surfaces of laser spatter particles.

surfaces

particles

laser


Input: Nano-oxide islands present on laser spatter coalesce to form large oxide islands.

laser

oxide


Input: Condensate is created from a large amount of superheat in the melt pool.

superheat

melt pool


Input: Heat-affected powder contains more delta ferrite than virgin powder.

powder

ferrite

virgin powder


Input: The selective laser melting process, commonly referred to as laser powder-bed fusion (L-PBF), is an Additive Manufacturing (AM) technique that uses a laser to fuse successive layers of powder into near fully dense components.

selective laser melting process

L-PBF

Additive Manufacturing

AM

fuse

as

powder

fusion

laser

fully dense

components


Input: Due to the large energy input from the laser during processing, vaporization causes instabilities in the melt pool leading to the formation of laser spatter and condensate, collectively known as heat-affected powder.

laser

laser

melt pool

as

powder


Input: Since heat-affected powder settles into the powder bed, the properties of the unconsolidated powder may be altered compromising its reusability.

powder

powder

be

powder bed

properties


Input: In this study, characterization of 304 L heat-affected powder was performed through particle size and shape distribution measurements, energy-dispersive spectroscopy, Raman spectroscopy, inert gas fusion, metallography, and x-ray diffraction.

powder

particle

distribution

spectroscopy

inert gas fusion

metallography

Raman spectroscopy

x-ray diffraction


Input: The results show morphological, chemical, and microstructural differences between the virgin powder and heat-affected powder formed during processing which aid in the understanding of laser spatter and condensate that form in the L-PBF process.

microstructural

virgin powder

powder

laser

L-PBF


Input: The impact of a rigid rod with a flat specimen fabricated of 3D-printed materials was analyzed.

impact

fabricated

rod


Input: An experimental setup has been designed in order to capture the motion of the rod during the impact using a high-speed camera.

experimental

impact

designed

rod

camera


Input: Image processing algorithms were developed to estimate the velocity before and after the impact as well as the coefficient of restitution.

Image

algorithms

impact

as

as


Input: Also, permanent deformations after the impact were scanned with an optical profilometer.

deformations

impact

optical


Input: In this work, a theoretical formulation for the contact force during the impact is proposed.

theoretical

impact

contact


Input: The impact was divided into two phases, compression and restitution, in which materials considered elastic–plastic in the first and fully elastic in the second one.

impact

materials

compression

elastic


Input: Results show a good correlation between the proposed formulation for the contact force and the behavior of materials.

contact

materials


Input: The objective of this work is to detect in situ the occurrence of lack-of-fusion defects in titanium alloy (Ti-6Al-4 V) parts made using directed energy deposition (DED) additive manufacturing (AM).

in situ

defects

titanium alloy

Ti-6Al-4 V

directed energy deposition

DED

additive manufacturing

AM


Input: We use data from two types of in-process sensors, namely, a spectrometer and an optical camera which are integrated into an Optomec MR-7 DED machine.

data

sensors

camera

DED machine

optical


Input: Both sensors are focused on capturing the dynamic phenomena around the melt pool region.

sensors

dynamic

melt pool


Input: To detect lack-of-fusion defects, we fuse (combine) the data from the in-process sensors invoking the concept of Kronecker product of graphs.

defects

data

fuse

sensors


Input: Subsequently, we use the features derived from the graph Kronecker product as inputs to a machine learning algorithm to predict the severity (class or level) of average length of lack-of-fusion defects within a layer, which is obtained from offline X-ray computed tomography of the test parts.

as

machine learning algorithm

average

defects

layer

X-ray computed tomography


Input: Accordingly, this work demonstrates the use of heterogeneous in-process sensing and online data analytics for in situ detection of defects in DED metal AM process.

heterogeneous

data analytics

in situ

defects

sensing

DED

AM process


Input: An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper.

additive manufacturing process

Extrusion

Ceramic

ceramic

process

three-dimensional

theoretical

density


Input: In this process, an aqueous paste of ceramic particles with a very low binder content (< 1 vol%) is extruded through a moving nozzle at room temperature.

process

ceramic

binder

extruded

nozzle

temperature


Input: After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides.

layer

layer

oil

surface

evaporation


Input: Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape.

Infrared

layer

yield stress


Input: The same procedure is repeated for every layer until part fabrication is completed.

layer

fabrication


Input: Several sample parts for various applications were produced using this process and their properties were obtained.

sample

process

properties


Input: The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.

fabrication

ceramic

complex geometries


Input: This manuscript expands the existing framework for single-material laser powder bed fusion printed dissolvable supports to Inconel 718 (IN718).

manuscript

framework

laser powder bed fusion

supports

Inconel 718


Input: Prior work with stainless steel leveraged a sensitization heat treatment using sodium hexacyanoferrate to precipitate chromium carbides over the top 100 μm to 200 μm of material, decreasing the corrosion resistance within this top layer relative to the bulk material.

stainless steel

sodium

precipitate

chromium carbides

material

material

heat treatment

corrosion resistance

layer


Input: The component is then etched at an anodic potential with a high selectivity toward the “sensitized” surface over the base component material.

component

component

surface


Input: This creates an etching process that self-terminates once the sensitized layer is removed.

etching

layer


Input: Additionally, the surface roughness of the component is often improved once the sensitized region is removed.

surface roughness

component


Input: In this work, two different sensitization heat schedules were investigated: 750 °C for 24 h to understand the impact of preferential chromium carbide precipitation and 1050 °C for 8 h to understand the impact of primary carbide precipitations.

heat

impact

impact

chromium carbide

carbide


Input: At 1050 °C, the formation of a protective oxide scale inhibits material removal in an electrolyte of 0.48 M HNO3.

oxide

material

electrolyte


Input: At 750 °C, 70 μm of material is removed after quenching to avoid the precipitation of corrosion resistant oxides.

material

oxides

quenching

precipitation

corrosion


Input: This manuscript investigates the effect of targeting different carbide precipitation regimes and oxides to produce an ideal microstructure for dissolvable supports post-sensitization.

manuscript investigates

microstructure

carbide

oxides

supports


Input: To demonstrate the utility of the process, the supports from a mock IN718 turbine blade were removed using this process.

process

process

supports


Input: One of the next avenues for Additive Manufacturing to develop is that of multi-material deposition in order to add functionality to the already complex geometries that are capable of being manufactured.

Additive Manufacturing

multi-material deposition

complex geometries

manufactured


Input: The purpose of this study was to investigate the effects of solid surface tensions, σsg − σsl, on the quality of printed lines, using 30–40 nm silver nanofluid ink.

surface tensions

quality

silver

ink


Input: The solid surface tensions of silver ink on glass and polytetrofluoroethylene (PTFE) substrates were determined theoretically, knowing characteristics of droplet.

surface tensions

silver ink

glass

PTFE

droplet


Input: Meanwhile, a Dimatix printer with nozzles of size of 21.5 μm was used to print conductive lines on smooth glass and PTFE substrates.

printer

nozzles

print

glass

PTFE


Input: The printed lines on glass were observed to be continuous with high quality of triple line, which was attributed to the high solid surface tensions of silver nanofluid ink on glass substrates.

glass

be

silver

ink

glass

quality

surface tensions


Input: The solid surface tensions of silver nanofluid ink were relatively low on PTFE, as results the printed lines were discontinuous.

surface tensions

silver

ink

PTFE

as


Input: The solid surface tensions were introduced as a reliable criterion to predict the printability of nanofluids.

surface tensions

as

printability


Input: The distribution of silver nanoparticles and layering phenomenon in silver nanofluid triple region on glass substrate was clearly observed, using environmental scanning electron microscopy (ESEM) for the first time.

distribution

nanoparticles

silver

silver

glass

scanning electron microscopy


Input: In addition to disjoining pressure, the size of droplet and affinity of nanofluid for substrate were observed to have important influences on spreading of nanoparticles in triple region.

pressure

droplet

nanoparticles

substrate


Input: Manufacturers struggle to produce low-cost, robust and intricate components in small batches.

components

small batches


Input: Additive processes like Fused Filament Fabrication (FFF) inexpensively generate such complex geometries, but potential defects may limit these components’ viability in critical applications.

Additive

Fused Filament Fabrication

FFF

complex geometries

defects

limit

components


Input: We present a high-accuracy, high-throughput and low-cost approach to automated non-destructive testing (NDT) for FFF interlayer delamination.

non-destructive testing

NDT

delamination

FFF


Input: This Artificially Intelligent (AI) approach utilizes Flash Thermography (FT) data processed with Thermographic Signal Reconstruction (TSR).

Flash

data

Reconstruction


Input: A Deep Neural Network (DNN) attains 95.4% per-pixel accuracy when differentiating four delamination severities 5 mm below the surface in PolyLactic Acid (PLA) widgets, and 98.6% accuracy in differentiating acceptable from unacceptable states for the same components.

Neural Network

delamination

surface

accuracy

accuracy

mm

PolyLactic Acid

PLA

components


Input: Automation supports time- and cost-efficient inspection for delamination defects in 100% of widgets, supporting FFF's use in critical and lot-size one applications.

Automation

delamination defects

inspection

FFF


Input: To identify the dominant contributing factor in the anomalously high strength of Al–Si-based alloys fabricated by selective laser melting (SLM), microstructural characteristics of a SLM-built Al–10Si–0.3 Mg alloy (AlSi10Mg) and their changes upon annealing at elevated temperatures were investigated.

strength

alloys

Mg alloy

selective laser melting

SLM

annealing

microstructural

temperatures


Input: The as-built AlSi10Mg alloy exhibits a peculiar microstructure comprising of a number of columnar α-Al (fcc) phase with concentrated Si in solution.

AlSi10Mg alloy

Si

microstructure

fcc

phase

solution


Input: At elevated temperatures, a number of Si phase (diamond structure) precipitates consumed the solute Si in the columnar α-Al phase, but the microstructure of the α-Al matrix changed slightly.

temperatures

Si

diamond

precipitates

Si

phase

phase

microstructure


Input: After annealing at elevated temperatures, the tensile strength of the as-built AlSi10Mg alloy substantially decreased accompanied by a reduction in the strain hardening rate.

annealing

strain hardening

temperatures

tensile strength

AlSi10Mg alloy

reduction


Input: The supersaturated solid solution of the α-Al phase containing numerous nano-sized particles enhanced the strain hardening, resulting in the anomalous strengthening of the SLM-built AlSi10Mg alloy.

solid solution

AlSi10Mg alloy

phase

particles

strain hardening

strengthening


Input: The microstructural features were formed due to rapid solidification at an extremely high cooling rate in the SLM process, which provides important insights into controlling the strength of Al–Si-based alloys fabricated by SLM.

microstructural

process

rapid solidification

SLM

SLM

cooling rate

strength

alloys


Input: The parametric design of graded porous scaffold based on TMPS surfaces was realized.

design

porous scaffold

surfaces


Input: The mechanical performance of SLM scaffolds was altered by tuning graded structures.

mechanical

SLM

scaffolds


Input: Graded structure played a key role in influencing deformation behavior of scaffolds.

structure

deformation

scaffolds


Input: Optimized heat treatment conditions improved mechanical properties of SLM scaffolds.

heat treatment

SLM

mechanical properties

scaffolds


Input: The rapid development of additive manufacturing technology makes it possible to fabricate parts with complex inner structures, especially for functionally graded scaffolds (FGS) in the field of bone tissue engineering.

additive manufacturing

fabricate

functionally graded

bone

engineering


Input: The parametric design of FGS is of great significance to the in-depth study of the effects of structural parameters of porous bone scaffolds on their mechanical properties and rehabilitation of patients.

design

parameters

mechanical properties

porous

bone scaffolds


Input: The present study proposed a parametric design method for FGS using a triply periodic minimal surface (TPMS).

design

triply periodic minimal surface


Input: Uniform and functionally graded samples were fabricated using selective laser melting of Ti-6Al-4V powder.

functionally graded

fabricated

selective laser melting

Ti-6Al-4V powder


Input: The FGSs successfully realized flexible control of structural parameters and showed comparable mechanical properties and permeability with natural bone tissue.

parameters

mechanical properties

permeability

bone


Input: Furthermore, heat treatment was verified to be an effective way to improve the ductility of TPMS-FGS.

heat treatment

be

ductility


Input: The deformation process and principal strain distribution of the FGSs were elucidated using a digital image correlation method.

deformation

distribution

digital image correlation

strain


Input: The FGSs proposed in the present study showed great potential in orthopedic implant or bone-substituting biomaterials.

implant

biomaterials


Input: Processing of Ti6Al4V and SS410 as a bimetallic joint using laser-based directed energy deposition (DED) system.

as

joint

directed energy deposition

DED


Input: Niobium (Nb) was used as a bond layer between the two immiscible base-materials.

Niobium

Nb

as

layer


Input: The bimetallic joint showed improved bond strength, both under compression and shear loading.

joint

bond strength

compression


Input: Proof-of-concept part demonstrated the application of the bimetallic joint by welding base metals, end-to-end, to the joint.

joint

joint

welding

base metals


Input: Bimetallic structures provide a unique solution to achieve site-specific functionalities and enhanced-property capabilities in engineering systems but suffer from bonding compatibility issues.

solution

bonding

engineering


Input: Materials such as titanium alloy (Ti6Al4 V) and stainless steel (SS410) have distinct attractive properties but are impossible to reliably weld together using traditional processes.

Materials

properties

processes

as

alloy

V

stainless steel

weld


Input: To this end, a laser-based directed energy deposition (DED) system was used to fabricate bimetallic joint of Ti6Al4 V and SS410 keeping niobium (Nb) as a diffusion barrier layer.

directed energy deposition

DED

fabricate

joint

diffusion

V

niobium

Nb

as

barrier layer


Input: Both shear and compression tests were used to characterize the joint’ s strength, and compared with the base materials.

compression tests

joint

materials

s


Input: The bimetallic-joint shear and compressive yield strengths were 419 ± 3 MPa (∼114% of SS410) and 560 ± 4 MPa (∼169% of SS410), respectively.

yield strengths

MPa

MPa


Input: The increase in interfacial shear and compressive yield strengths over the base material indicates strong metallurgical bonding between the base materials and the interlayer, Nb.

yield strengths

material

Nb

metallurgical bonding

materials


Input: Proof-of-concept part for direct application of the bimetallic joint was demonstrated by welding base metals, end-to-end, to the joint.

joint

joint

welding

base metals


Input: The interfacial microstructures, elemental diffusion and phases, including failure modes were examined using secondary and backscatter electron imaging, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS).

microstructures

diffusion

failure modes

imaging

X-ray diffraction

XRD

energy dispersive spectroscopy

EDS


Input: The bimetallic-joint interfaces were free from brittle intermetallic compounds such as FeTi and Fe2Ti that are generally responsible for weak bond strength.

brittle

as

bond strength


Input: Selective laser melting (SLM) is widely gaining popularity as an alternative manufacturing technique for complex and customized parts.

Selective laser melting

SLM

manufacturing

as


Input: SLM is a near net shape process with minimal post processing machining required dependent upon final application.

SLM

near net shape

machining

post processing


Input: The fact that SLM produces little waste and enables more optimal designs also raises opportunities for environmental advantages.

SLM

designs


Input: The use of aluminium (Al) alloys in SLM is still quite limited due to difficulties in processing that result in parts with high degrees of porosity.

aluminium

Al

alloys

SLM

degrees of porosity


Input: However, Al alloys are favoured in many high-end applications for their exceptional strength and stiffness to weight ratio meaning that they are extensively used in the automotive and aerospace industries.

Al alloys

strength

stiffness to weight ratio

automotive

aerospace industries


Input: This study investigates the windows of parameters required to produce high density parts from AlSi10Mg alloy using selective laser melting.

investigates

parameters

density

AlSi10Mg alloy

selective laser melting


Input: Modelling the thermal behaviour of the melt pool produced in Laser Powder-Bed Fusion (L-PBF) processes is not an easy task, as many complex non-linear thermal phenomena are involved.

Modelling

Laser

melt pool

as

Fusion

processes

L-PBF


Input: An effective way to make the computational cost of these analyses affordable is to model powder and molten metal as continuous media, wherein all the heat transfer modes occurring in the liquid are simulated as lumped fictitious heat conduction.

model

heat transfer

heat conduction

molten metal

as

as


Input: The augmentation factor used to enhance the thermal conductivity of the liquid is in general calibrated through experimental estimations of the melt pool size.

thermal conductivity

calibrated

experimental

melt pool


Input: The present work is aimed at devising a robust method for the calibration of such thermal parameters.

calibration

parameters


Input: A specific point of novelty of the present paper is the definition of a method to correlate surface roughness and numerically predicted melting pool size.

surface roughness

predicted melting


Input: This strategy is able to predict with good accuracy the roughness of L-PBF fabricated parts and could pave the way for calibration strategies based on roughness measurements.

accuracy

roughness

roughness

L-PBF

fabricated

calibration


Input: For this purpose, a 3-factor, 3-level Design of Experiment (DoE) has been carried out to investigate melting pool size and roughness by changing the machine process parameters: laser power, hatch distance, time exposure.

Design of Experiment

parameters

exposure

melting

roughness

machine

laser power

hatch distance


Input: In this way, the calibration of the thermal properties is made less sensitive to the large uncertainty usually affecting the melt pool size measurements and the range of applicability of the thermal model is explored over a broad spectrum of L-PBF process parameters.

calibration

thermal properties

model

parameters

melt pool

range

L-PBF


Input: Anisotropic and isotropic enhanced thermal conductivity approaches are applied in combination with a laser source modelled either as a 2D or 3D heat source, respectively.

Anisotropic

isotropic

thermal conductivity

laser source

as

source


Input: The latter approach proved to be more accurate and robust against experimental uncertainties.

be

accurate

experimental


Input: Fused Filament Fabrication (FFF), one of the most popular processes of 3D printing, offers flexibility in manufacturing and introduces anisotropic properties to the final parts.

Fused Filament Fabrication

FFF

3D printing

processes

flexibility in manufacturing

anisotropic


Input: With the use of Curvilinear Variable Stiffness (CVS) 3D printing technology, mechanical properties of the manufactured products can be further improved and optimized.

Stiffness

3D printing technology

mechanical properties

manufactured products

be


Input: In this work, we demonstrate how CVS design can improve open-hole tensile strength and failure strain of the manufactured specimens per ASTM D5766.

design

tensile strength

failure

manufactured


Input: In addition, the ratio of the specimen width to the hole diameter is considered as a design parameter and investigated.

diameter

as

design


Input: It is found that CVS design improves the failure strength by 38.0% for a larger hole diameter configuration (from 48.0 MPa to 66.2 MPa), while the improvement in failure strain (from 0.0125 mm/mm to 0.0130 mm/mm) is limited to only 4.0%.

design

failure

diameter configuration

MPa

MPa

failure


Input: On the other hand, for a smaller hole diameter case, a substantial improvement of 52.5% in failure strain is obtained with the use of CVS design (from 0.0141 mm/mm to 0.0215 mm/mm), while 16.7% improvement in failure stress (76.0 MPa to 88.6 MPa) is less pronounced.

diameter

failure

failure

MPa

MPa

design


Input: During part fabrication by laser powder-bed fusion (L-PBF), an Additive Manufacturing process, a large amount of energy is input from the laser into the melt pool, causing generation of spatter and condensate, both of which have the potential to settle in the surrounding powder-bed compromising its reusability.

fabrication

L-PBF

Additive Manufacturing process

laser

laser

fusion

melt pool

spatter


Input: In this study, AISI 304 L stainless steel powder is subjected to seven reuses in the L-PBF process to assess the changes in powder properties that occur as a result of successive recycling.

AISI 304

stainless steel

powder

powder

as

L-PBF

recycling


Input: The powder was characterized morphologically by particle size and shape distribution measurements, chemically through inert gas fusion for evaluation of oxygen content, and microstructurally by X-ray diffraction for phase identification.

powder

oxygen

particle

distribution

inert gas fusion

phase

X-ray diffraction


Input: The evolution in powder properties was used to explain observed performance differences obtained by the Hausner ratio and a Revolution Powder Analyzer for quantifying flowability.

evolution

performance

powder

Powder


Input: The results show that recycled powder coarsens and becomes more spherical, accrues oxygen, and accumulates delta ferrite as it is reused.

recycled

spherical

powder

oxygen

ferrite

as


Input: Due to the change in powder morphology, recycled powder exhibited improved flowability in comparison to the virgin powder.

powder

powder

virgin powder

morphology

recycled


Input: The energy per layer was found to be critical factor to print fully dense AlSi12 samples using SLM process.

layer

fully dense

be

print

SLM

process


Input: The printing area along the build direction varies when a sample is built in different orientations.

area

build direction

sample

orientations


Input: The anisotropy of SLM-built samples corresponds to the variable energy per layer and printing area.

anisotropy

samples

layer

area


Input: Fully dense SLM-built AlSi12 samples were printed by using energy per layer in an optimum range.

Fully dense

layer

range


Input: The anisotropy in the tensile properties of AlSi12 alloy fabricated using selective laser melting (SLM) additive manufacturing process was investigated.

anisotropy

tensile properties

alloy

selective laser melting

SLM

additive manufacturing process


Input: The tensile samples were printed in three different orientations, horizontal (H-0°), inclined (I-45°), and vertical (V-90°), and found to exhibit yield strength between 225 MPa and 263 MPa, tensile strength between 260 MPa and 365 MPa, and ductility between 1 and 4%, showing distinct fracture patterns.

tensile

yield strength

tensile strength

ductility

samples

orientations

vertical

MPa

MPa

MPa

MPa

fracture

V


Input: It was established that the build orientation had insignificant effect on the microstructural characteristics of the SLM-printed samples, while XRD phase analysis showed variations in the Al (111) and Al (200) peak intensities.

build orientation

microstructural

samples

phase

variations

XRD

Al

Al


Input: Consequently, the anisotropy in the mechanical properties of the SLM-printed AlSi12 samples was attributed to the differences in their relative density.

anisotropy

relative density

mechanical properties


Input: Although the energy density was kept constant when printing the samples along different orientations, the “energy per layer” was found to be different owing to the variation in the printing area along the build direction.

energy density

layer

area

build direction

samples

orientations

variation

be


Input: Further investigation on the effect of printing area, and correspondingly energy per layer, on the relative density was carried out.

area

layer

relative density


Input: It was found that energy per layer in the range of 504–895 J yielded ≥99.8% relatively dense AlSi12 SLM-printed samples.

layer

range

samples


Input: This study puts forth a new idea that the density of the SLM-printed samples could be controlled using energy per layer as an input process parameter.

density

samples

process parameter

be

as

layer


Input: Polyvinylidene fluoride (PVDF) is a polymer prized for its unique material properties, including a high resistance to corrosive acids such as HCL and HF and its piezoelectric potential based on the proper microstructure arrangement.

polymer

as

HF

material properties

microstructure

resistance

corrosive


Input: In this work, the effects of fused filament fabrication (FFF) routine parameters on printed PVDF film properties were investigated using a variety of experimental methods.

fused filament fabrication

FFF

parameters

properties

experimental


Input: The influence of in-fill angle (0°, 45°, and 90°) on the effective Young’ s Modulus, Poisson’ s ratio, and yield strength were evaluated using tensile testing and a digital image correlation (DIC) analysis.

s

s

yield strength

tensile testing

digital image correlation

DIC


Input: The phase content, in particular the β-phase amount, within the semi-crystalline PVDF films was determined as a function of processing parameters using the FTIR method.

phase

parameters

as

FTIR


Input: Considered parameters included the extrusion temperature, horizontal speed, in-situ applied hot end voltage, and bed material.

parameters

in-situ

extrusion

hot end

bed


Input: Results showed that higher β-phase content was associated with lower extrusion temperatures, faster extrusion rates, and higher hot end voltages.

extrusion

extrusion rates

hot end


Input: New advancements in 3D printing enable manufacturing a solid part with spatially controlled and varying material properties; this research seeks to establish techniques for finding optimal designs that use this new technology for the greatest structural benefit.

3D printing

manufacturing

material properties

research

technology

designs


Input: We describe the use of a sequential quadratic programming based optimization solver to find an optimal distribution of material properties that minimize strain energy gradients, as calculated using finite element analysis.

optimization

distribution

material properties

finite element analysis

strain

as


Input: This design method is applied to the case of a flat thin plate with a hole, and has been proven to successfully reduce strain energy gradients and therefore stress concentrations.

design

strain

stress concentrations


Input: The optimally designed plates are 3D printed using a novel technology that uses vat polymerization technology.

designed

3D printed

vat polymerization

technology

technology


Input: The computational model is validated with experiments.

computational model


Input: Enabling design engineers to customize material properties around geometric discontinuities will provide greater flexibility in reducing stress concentrations without modifying geometry or adding additional supports.

design

material properties

geometry

flexibility

stress concentrations

supports


Input: Laser Engineered Net Shaping (LENS) is an additive manufacturing technique that belongs to the ASTM standardized directed energy deposition category.

Laser Engineered Net Shaping

LENS

additive manufacturing

directed energy deposition


Input: To date, very limited work has been conducted towards understanding the fatigue crack growth behavior of LENS fabricated materials, which hinders the widespread adoption of this technology for high-integrity structural applications.

fatigue crack growth

fabricated

technology

LENS


Input: In this study, the propagation of a 20 μm initial crack in LENS fabricated Ti-6Al-4V was captured in-situ, using high-energy synchrotron x-ray microtomography.

LENS

fabricated

in-situ

synchrotron


Input: Fatigue crack growth (FCG) data were then determined from 2D and 3D tomography reconstructions, as well as from fracture surface striation measurements using SEM.

Fatigue crack growth

data

fracture

as

as

striation

SEM


Input: The observed agreement demonstrates that x-ray microtomography and fractographic analysis using SEM can be successfully combined to study the propagation behavior of fatigue cracks.

x-ray microtomography

fractographic analysis

SEM

be

fatigue


Input: A finite element model of Laser Powder Bed Fusion (LPBF) process applied to metallic alloys at a mesoscopic scale is presented.

finite element model

process

Laser Powder Bed Fusion

LPBF

metallic alloys


Input: This Level-Set model allows to follow melt pool evolution and track development during building.

model

evolution

melt pool


Input: A volume heat source model is used for laser/powder interaction considering the material absorption coefficients, while a surface heat source is used to consider the high laser energy absorption by dense metal alloys.

volume

heat source

absorption

surface

heat source

laser energy

absorption

material

metal alloys


Input: Shrinkage during consolidation from powder to dense material is modelled by a compressible Newtonian constitutive law.

Shrinkage

consolidation

powder

material


Input: An automatic remeshing strategy is also used to provide a good compromise between accuracy and computing time.

remeshing

accuracy


Input: Different cases are investigated to demonstrate the influence of the vaporisation phenomena, of material properties and of laser scan strategy on bead morphology.

material properties

bead morphology

laser scan


Input: Due to the layer-based nature of the powder bed fusion (PBF) process, part surfaces oriented in space at varying angles with respect to the build direction are differently affected by a wide array of manufacturing-induced phenomena (staircase effects, spatter, particles, etc.

powder bed fusion

PBF

process

surfaces

particles

build direction

spatter


Input: For assessing surface topography of PBF surfaces most researchers have looked at surface texture parameters (profile-ISO 4287 and areal-ISO 25178−2).

surface topography

parameters

PBF

surface texture

profile

ISO

ISO


Input: Texture parameters provide useful summaries of surface-wide properties, but do not allow the analysis to focus on specific topographic formations of interest.

Texture

parameters

properties


Input: In this work, the topography of electron beam powder bed fusion (EBPBF) surfaces as a function of orientation with respect to the build direction was investigated using a combined approach consisting of both texture parameters and feature-based characterisation.

topography

electron beam

surfaces

orientation

parameters

bed fusion

as

build direction

texture


Input: A custom-designed test part featuring surfaces at different orientations was measured with a focus variation instrument.

surfaces

orientations

variation


Input: A feature-based characterisation pipeline was implemented for the identification, isolation and geometrical characterisation of spatter formations and particles present on the as-built surfaces.

spatter

particles

surfaces


Input: The surfaces deprived of the identified features were then characterised by means of conventional ISO 25178−2 texture parameters.

surfaces

parameters

ISO

texture


Input: The results confirm that combining feature-based characterisation with conventional analysis through texture parameters creates new perspectives for looking at EBPBF surfaces, thus better supporting future research endeavours aimed at achieving a more comprehensive insight on the nature of EBPBF surfaces.

texture

parameters

surfaces

research

surfaces


Input: For the first time quantitative results are provided on number, shape and localisation of spatter and other particles in EBPBF surfaces as a function of build orientation, and texture parameters are provided that describe the fabricated surfaces in a more reliable way as particles and spatter formations have been removed.

quantitative

particles

surfaces

parameters

fabricated

spatter

spatter

as

as

build orientation

texture


Input: Unimodal powder samples were used in the laser sintering process.

powder

laser sintering


Input: Different powder particle size and laser scan speeds were used.

powder particle

laser scan


Input: Microphotography, bulk density and tensile strength of artefact were measured.

density

tensile strength


Input: Neck size and strength were estimated with the Rumpf model for the strength of powder aggregates.

strength

strength

model

powder aggregates


Input: Sintering temperatures were estimated with the Frenkel model for the effect of time on the sintering process.

Sintering

sintering

model

process


Input: Selective Laser Sintering (SLS) of ceramic powders is studied in order to understand how the initial material properties and the process conditions affect the degree of sintering/melting and the mechanical properties of the sintered material.

Selective Laser Sintering

SLS

sintered

ceramic powders

material

material properties

process

mechanical properties


Input: Unimodal powder samples of different narrow particle size distributions between 16 and 184 μm were sintered with a 40 W CO2 laser, using laser scan speeds of either 50 or 100 mm s−1 and, in both cases, a scanning energy of 160 J m−1.

powder

particle size distributions

scanning

sintered

mm

laser scan


Input: The sintered material was studied by means of optical and SEM microphotography and characterized in terms of bulk density and tensile strength.

sintered

material

optical

SEM

density

tensile strength


Input: The Rumpf approach to relate interparticle forces to the strength of powder agglomerates was used in this work to estimate the average strength of the sintered interparticle contacts starting from the tensile strength of specimens.

forces

average

strength

tensile strength

powder

sintered

contacts


Input: In turn, the average strength of the neck contact was used to estimate the size of the neck of fused material between two sintered particles.

average

fused

particles

contact

sintered


Input: These data coupled with the Frenkel model for particle sintering allowed an estimate of the sintering temperature for the different experimental conditions tested.

data

model

particle

experimental

sintering


Input: The temperatures found are consistent with the glass transition temperature of the material used.

temperatures

glass transition temperature

material


Input: The effect of particle size and scanning speed is assessed and discussed.

particle

scanning speed


Input: The Z axis table motion errors and laser positioning errors an EOSINT M280 were evaluated using a set of standard metrology techniques and instrumentation.

errors

errors

standard

metrology

laser

set


Input: While the linear displacement error of the table is quite low (4.5 μm), straightness, yaw and pitch errors on the other hand were significantly higher and may contribute from 20 to 30 microns of form and orientation tolerances over a large size build.The performance of the laser positioning system was much worse.

error

straightness

errors

orientation

performance

laser


Input: A designed artifact was produced, and used to evaluate the laser performance against a set of tolerance controls extracted from the ASME Y14.5-2009 Standard.

designed

tolerance controls

laser

set

extracted

Standard


Input: The largest tolerance magnitude (239 μm) was calculated as the combined effect of location, orientation, size and form errors in the trace of a large quadrifolium etched over the working area of the laser.

tolerance magnitude

area

as

orientation

errors

laser


Input: The errors measured in this research are substantial.

errors

research


Input: Selective laser melting was utilized to fabricate Sc and Zr modified Al-Mg alloy.

Selective laser melting

fabricate

Zr

Al-Mg alloy


Input: Different precipitation behavior between various scan speeds are characterized by SEM and TEM.

precipitation

scan speeds

SEM

TEM


Input: Significant improvement of hardness is evaluated and explained under a relative low scan speed.

hardness

scan speed


Input: Relationships between scan speed, precipitate distribution, and the resultant mechanical properties are elucidated.

scan speed

precipitate

distribution

mechanical properties


Input: The interest of selective laser melting (SLM) Al-based alloys for lightweight applications, especially the rare earth element Sc modified Al-Mg alloy, is increasing.

selective laser melting

SLM

alloys

element

Al-Mg alloy

lightweight


Input: In this work, high-performance Al-Mg-Sc-Zr alloy was successfully fabricated by SLM.

alloy

fabricated

SLM


Input: The phase identification, densification behavior, precipitate distribution and mechnical properties of the as-fabricated parts at a wide range of processing parameters were carefully characterized.

phase

distribution

properties

parameters

densification

precipitate

range


Input: Meanwhile, the evolution of nanoprecipitation behavior under various scan speeds is revealed and TEM analysis of precipitates shows that a small amount of spherical nanoprecipitates Al3 (Sc, Zr) were embedded at the bottom of the molten pool using a low scan speed.

evolution

spherical

molten pool

scan speeds

scan speed

TEM

precipitates

Zr


Input: While no precipitates were found in the matrix using a relatively high scan speed due to the combined effects of the variation of Marangoni convection vector, ultrashort lifetime of liquid and the rapid cooling rate.

precipitates

scan speed

cooling rate

variation


Input: An increased hardness and a reduced wear rate of 94 HV0.2 and 1.74 × 10−4 mm3N-1 m-1 were resultantly obtained respectively as a much lower scan speed was applied.

hardness

wear

as

scan speed


Input: A relationship between the processing parameters, the surface tension, the convection flow, the precipitation distribution and the resultant mechanical properties has been well established, demonstrating that the high-performance of SLM-processed Al-Mg-Sc-Zr alloy could be tailored by controlling the distribution of nanoprecipitates.

parameters

precipitation

distribution

mechanical properties

distribution

surface tension

alloy

be


Input: Continuous carbon nanotube (CNT) yarn filaments can be employed as an inherently multifunctional feedstock for additive manufacturing (AM).

carbon nanotube

CNT

yarn filaments

be

as

feedstock

additive manufacturing

AM


Input: With this material, it becomes possible to use a single material to impart multiple functionalities in components and take advantage of the tailorability offered by fused filament fabrication (FFF) over conventional fabrication techniques.

material

material

components

fused filament fabrication

FFF

fabrication


Input: Some of the challenges associated with coupling this emerging material with advanced processing are addressed here through the fabrication and characterization of additively manufactured functional objects.

material

fabrication

additively manufactured


Input: Continuous CNT yarn reinforced Ultem® specimens are characterized to determine their mechanical and electrical properties.

CNT

reinforced

electrical properties

mechanical


Input: The potential to produce net shape fabricated multifunctional components is demonstrated by additively manufacturing a quadcopter frame using Ultem® and continuous CNT yarn reinforced Ultem®, where the CNT yarn reinforcement was designed to also act as the electrical conductors carrying current to the motors.

net shape

manufacturing

fabricated

reinforced

components

CNT

CNT

as

conductors

reinforcement

designed

electrical


Input: A computational modeling approach to simulate residual stress formation during the electron beam melting (EBM) process within the additive manufacturing (AM) technologies for Inconel 718 is presented in this paper.

modeling

residual stress

electron beam melting

EBM

additive manufacturing

AM

process

technologies

Inconel 718


Input: The EBM process has demonstrated a high potential to fabricate components with complex geometries, but the resulting components are influenced by the thermal cycles observed during the manufacturing process.

EBM

fabricate

manufacturing process

components

components

complex geometries

thermal cycles


Input: When processing nickel based superalloys, very high temperatures (approx.

nickel based superalloys

temperatures


Input: 1000 °C) are observed in the powder bed, base plate, and build.

powder bed

build


Input: These high temperatures, when combined with substrate adherence, can result in warping of the base plate and affect the final component by causing defects.

temperatures

substrate

warping

defects

component


Input: It is important to have an understanding of the thermo-mechanical response of the entire system, that is, its mechanical behavior towards thermal loading occurring during the EBM process prior to manufacturing a component.

thermo-mechanical

thermal loading

mechanical

EBM

manufacturing

component


Input: Therefore, computational models to predict the response of the system during the EBM process will aid in eliminating the undesired process conditions, a priori, in order to fabricate the optimum component.

computational models

EBM

fabricate

process

component


Input: Such a comprehensive computational modeling approach is demonstrated to analyze warping of the base plate, stress and plastic strain accumulation within the material, and thermal cycles in the system during different stages of the EBM process.

modeling

warping

stress

plastic

material

thermal cycles

EBM


Input: Parts made by fused filament fabrication differ in their mechanical properties from the parent material.

fused filament fabrication

mechanical properties

material


Input: To investigate the effect of the manufacturing process on the mechanical properties of 3D-printed parts, a series of experiments including Dynamic Mechanical Analysis (DMA) and ultrasonic wave propagation were conducted.

manufacturing process

mechanical properties

Dynamic Mechanical Analysis

DMA

3D-printed parts


Input: For this purpose, printed parts were made from custom ABS filament and were printed using a rectangular bead shape to minimize porosity.

ABS

bead

porosity


Input: The main properties investigated included the elastic, loss and storage moduli, and the material loss tangent (tan δ).

properties

elastic

material


Input: Results indicate that the elastic modulus of the printed material was somewhat lower than that of the parent material, about 2 GPa for frequencies 0.1 Hz–100 Hz.

elastic modulus

GPa

material

material


Input: Droplet jetting behavior largely determines the final drop deposition quality in the inkjet printing process.

Droplet

deposition quality

inkjet printing process


Input: Forming such behavior is governed by the fluid flow pattern.

Forming

fluid flow