Input: In this contribution, a simplified macroscopic and semi-analytical thermal analysis of directed energy deposition (DED) is presented to obtain computationally efficient simulations of the entire process.

macroscopic

process

thermal analysis

directed energy deposition

DED

simulations


Input: Solidification and solid-state phase transitions are taken into account.

Solidification

solid-state phase


Input: The model is derived for laser metal powder directed energy deposition, although it can be simply adapted for other focused thermal energy (e.g., electron beam, or plasma arc).

model

thermal energy

electron beam

plasma arc

laser

powder

be

directed energy deposition


Input: The gas flow used for carrying the powder significantly influences cooling conditions, which is included in the model.

gas

model

powder

cooling


Input: The proposed simulation strategy applies to multilayer composites with a wide range of shapes in the horizontal plane and arbitrary laser scanning strategies (continuous way, back and forth, etc.).

simulation

laser

composites

range


Input: The proposed work provides a simple tool to study the influence of most process parameters, design in situ experiments and in turn develop optimization loops to reach material requirements and specific microstructures.

simple

process parameters

optimization

design

material

microstructures


Input: In situ pyrometer measurements have been compared to the model, and good agreement has been observed with 2.6% error in average.

In situ

model

error

average


Input: The model is used to demonstrate the effect of various process parameters for a simple cylindrical geometry and a more complex auxetic cell.

model

process parameters

cylindrical

simple

cell


Input: Additive manufacturing using nanoparticles (NPs) is a growing field due to the ever-increasing demand for parts with smaller and smaller features.

Additive manufacturing

nanoparticles


Input: Of particular interest are copper nanoparticles (Cu NPs) due to the ubiquitous use of Cu in microelectronics applications.

copper

Cu

Cu

microelectronics


Input: There are numerous methods currently available to synthesize Cu NPs in both powder and ink forms.

Cu

powder

ink


Input: However, the effect of how the NPs are manufactured on the sintering properties of the NPs produced is not well understood.

manufactured

properties

sintering


Input: This paper shows that NP size, morphology, and synthesis method can have a significant effect on the sintering temperature and sintering quality for Cu NPs.

morphology

quality

sintering

sintering

Cu


Input: In addition, surface coatings and surfactants used in Cu NP inks can help to reduce agglomeration in the dried NP samples, prevent oxidation of the Cu NPs, and restrict the sintering of the Cu NPs at lower temperatures due to the need to thermally remove the surface coatings before sintering can occur.

surface

samples

surface

coatings

coatings

Cu

Cu

Cu

dried

oxidation

sintering

sintering

temperatures


Input: Therefore, these coatings improve the Cu NP packing density and increase the temperature required for necking to occur which leads to better sintering of the Cu NP ink samples.

coatings

Cu

Cu

ink

density

temperature

necking

sintering


Input: It is also observed in this paper that most of these surface coatings are removed during the sintering processes leaving the sintered parts with a much higher Cu percentage than contained in the original NPs.

surface

processes

coatings

sintering

sintered

Cu


Input: However, at temperatures near the melting temperature of the Cu NPs, the surface coatings can start to graphitize and hinder the fusion of the NPs.

temperatures

melting temperature

Cu

surface

fusion

coatings


Input: Therefore, the optimal sintering conditions for Cu NP inks are at temperature high enough to break down the polymer surface coating on the NPs but low enough that the Cu NPs do not start to melt and that graphitizing of the surface coatings does not start to occur.

sintering

Cu

polymer

Cu

temperature

coating

coatings

melt

surface


Input: In the present study, 420 stainless steel parts with different porosities in the range of ∼6% to ∼ 54% were fabricated via the binder jet printing technology followed by pre-sintering between 1000 and 1400 °C.

420 stainless steel

binder

porosities

range

fabricated

printing technology

pre-sintering


Input: Initially, during the pre-sintering at 1150 °C, evidences of neck formation between the 420 stainless steel particles were observed.

pre-sintering

420 stainless steel


Input: Later, when pre-sintered at higher temperature between 1300 and 1350 °C, the parts were found with 3D interconnected open-porous channels.

pre-sintered

temperature


Input: Finally, pre-sintering at 1400 °C led to closed/isolated pores within the parts.

pre-sintering

led

pores


Input: Subsequent bronze infiltration into the as-built (without pre-sintering) and pre-sintered (< 1350 °C) 420 stainless steel parts with open porous channels were carried out successfully and their corresponding microstructures and mechanical properties were presented and discussed.

bronze

420 stainless steel

microstructures

pre-sintering

pre-sintered

porous

mechanical properties


Input: Relatively more uniform bronze infiltration was able to be achieved for the parts pre-sintered between 1300 and 1350 °C due to the presence of 3D interconnected open-porous channels.

bronze

be

pre-sintered


Input: When compared to the as-built parts, the combination of pre-sintering at 1350 °C and subsequent bronze infiltration led to a significant increase in the tensile properties exhibiting a maximum tensile yield strength and ultimate tensile strength of ∼ 647 and ∼ 1053 MPa, respectively.

pre-sintering

bronze

led

tensile properties

tensile

strength

ultimate tensile strength

MPa


Input: The fractured surfaces indicated a typical brittle mode of fracture with cleavages on the 420 stainless steel matrix whereas dimples and ridges were observed within the bronze phase.

surfaces

fracture

brittle

420 stainless steel

bronze


Input: Characterization of the local deformation of the microstructure of 316L stainless steel single-track thickness walls.

deformation

microstructure

316L stainless steel


Input: EBSD and DIC analysis of material elements under in situ SEM tensile loading.

EBSD

DIC

in situ

material elements

tensile


Input: Crystallographic morphology and texture aligned with heat flow pattern induced by printing strategy.

morphology

heat flow pattern

texture


Input: Statistical analysis of morphology and strain patterns for small and large grains.

morphology

grains

strain


Input: Relationship between grain's morphology, strain patterns and anisotropy of macroscopic behavior.

grain

morphology

macroscopic

strain

anisotropy


Input: In additive manufacturing, the process parameters have a direct impact on the microstructure of the material and consequently on the mechanical properties of the manufactured parts.

additive manufacturing

process parameters

impact

microstructure

mechanical properties

manufactured

material


Input: The purpose of this paper is to explore this relation by characterizing the local microstructural response via in situ tensile test under a scanning electron microscope (SEM) combined with high resolution digital image correlation (HR-DIC) and Electron Backscatter Diffraction (EBSD) maps.

microstructural

in situ

digital image correlation

scanning electron microscope

SEM

Electron Backscatter Diffraction

EBSD

high resolution


Input: The specimens under scrutiny were extracted from bidirectionally-printed single-track thickness 316L stainless steel walls built by directed energy deposition.

extracted

316L stainless steel

directed energy deposition


Input: The morphologic and crystallographic textures of the grains were characterized by statistical analysis and associated with the particular heat flow pattern of the process.

grains

heat flow pattern

process


Input: Grains were sorted according to their size into large columnar grains located within the printed layer and small equiaxed grains located at the interfaces between successive layers.

Grains

equiaxed grains

columnar grains

layer


Input: In situ tensile experiments were performed with a loading direction either perpendicular or along the printing direction and exhibit different mechanisms of deformation.

In situ

deformation


Input: A statistical analysis of the average deformation per grain indicates that for a tensile loading along the building direction, small grains deform less than the large ones.

average

grain

grains

tensile

building direction


Input: In addition, HR-DIC combined with EBSD maps showed strain localization situated at the interface between layers in the absence of small grains either individual or in clusters.

EBSD

strain

interface

grains


Input: For tensile loads along the printing direction, the strain localization was present in several particular large grains.

tensile loads

strain

grains


Input: These observations permit to justify the differences in yield and ultimate strength noticed during macroscopic tensile tests for both configurations.

ultimate strength

macroscopic


Input: Moreover, they indicate that an optimization of the process parameters could trigger the control of microstructure and consequently the macroscopic mechanical behavior.

optimization

process parameters

microstructure

macroscopic


Input: Strategies for fabricating iron-based materials with high strength and ductility are rare despite intense research efforts within the last decades.

fabricating

materials

research

strength

ductility


Input: This study provides a novel approach to achieve the synthesis of highly strong and ductile iron-based composites reinforced with a high weight fraction of WC particles (20 wt%) utilizing laser powder bed fusion (LPBF) as processing technique.

ductile

composites

WC

as

weight

fraction

particles

laser powder bed fusion

LPBF


Input: Thereby, the LPBF-fabricated composite material has a multi-phase microstructure consisting of ductile austenite (main phase), highly strong martensite and carbidic precipitations extending across different length-scales.

composite material

austenite

martensite

microstructure

phase

ductile


Input: The precipitation of (Fe, W) 3C type carbide at the Fe/WC interface is well controlled.

precipitation

interface

Fe

carbide


Input: Thus, a very thin reaction layer (< 500 nm) forms between the WC particles and iron-based matrix.

layer

WC

particles


Input: These iron-based composites synthesized by LPBF show an excellent compressive strength of about 2833 MPa and large fracture strain of about 32%.

composites

LPBF

compressive strength

MPa

fracture


Input: The following mechanisms contribute to the improved mechanical properties: (1) multiphase material system, (2) grain refinement, (3) substructures, (4) coherent multiscale interfaces and (5) nano-precipitations.

mechanical properties

material

grain refinement


Input: Laser powder bed fusion (LPBF) is a proven additive manufacturing (AM) technology for producing metallic components with complex shapes using layer-by-layer manufacture principle.

Laser powder bed fusion

LPBF

additive manufacturing

AM

technology

layer-by-layer

metallic

components

complex shapes


Input: However, the fabrication of crack-free high-performance Ni-based superalloys such as Hastelloy X (HX) using LPBF technology remains a challenge because of these materials’ susceptibility to hot cracking.

fabrication

LPBF

superalloys

as

materials

hot cracking

susceptibility


Input: This paper addresses the above problem by proposing a novel method of introducing 1 wt.% titanium carbide (TiC) nanoparticles.

titanium carbide

nanoparticles


Input: The findings reveal that the addition of TiC nanoparticles results in the elimination of microcracks in the LPBF-fabricated enhanced HX samples; i.e.

nanoparticles

microcracks

samples


Input: the 0.65% microcracks that were formed in the as-fabricated original HX were eliminated in the as-fabricated enhanced HX, despite the 0.14% residual pores formed.

microcracks

residual

pores


Input: It also contributes to a 21.8% increase in low-angle grain boundaries (LAGBs) and a 98 MPa increase in yield strength.

grain boundaries

MPa

yield strength


Input: The study revealed that segregated carbides were unable to trigger hot cracking without sufficient thermal residual stresses; the significantly increased subgrains and low-angle grain boundaries played a key role in the hot cracking elimination.

carbides

hot cracking

subgrains

grain boundaries

hot cracking

residual stresses


Input: These findings offer a new perspective on the elimination of hot cracking of nickel-based superalloys and other industrially relevant crack-susceptible alloys.

hot cracking

nickel-based superalloys

alloys


Input: The findings also have significant implications for the design of new alloys, particularly for high-temperature industrial applications.

design

alloys

industrial


Input: Additive manufacturing (AM) has the potential to construct complex geometries through the simple and highly repetitive process of layer-by-layer deposition.

Additive manufacturing

AM

simple

complex geometries

process

layer-by-layer deposition


Input: The process is repetitive and fully automated, but the interactions between layers during deposition are tightly coupled.

process

deposition


Input: To unravel these interactions, the computational models of the manufacturing process are critically needed.

computational models

manufacturing process


Input: However, current state-of-the-art physics-based models are computationally demanding and can not be used for any realistic optimization.

state-of-the-art

physics-based models

optimization

be


Input: To address this challenge, we built a surrogate model (SM) of thermal profiles that significantly reduced the computational cost.

model

thermal profiles

SM


Input: We built this model based on the observation that any AM process exhibits a high level of redundancy and periodicity, making it an ideal problem for machine learning and surrogate modeling.We introduced a unique geometry representation that is the key insight for this work.

model

geometry

AM process

machine


Input: Rather than directly using the part geometry, we directly use the GCode and translate it into a set of features (local distances from heat sources, e.g., extruder, and sinks, e.g., cooling surfaces).

geometry

heat sources

set

extruder

cooling


Input: This set of features is directly used as an input for the SM of thermal history.

set

as

SM


Input: Since this set can be calculated a priori from GCode, the explicit geometry considerations are largely factored out.

set

be

geometry


Input: Moreover, we leveraged the analytical solution to the moving heat source model to determine heat influence zone (HIZ).

analytical solution

heat source

heat


Input: We showed that for fused filament fabrication, the size of HIZ is small; thus, the number of input variables for the SM is small as well.To build the SM, we first generated the thermal data using a physics-based model and use it to train an artificial neural network model.

fused filament fabrication

SM

as

SM

build

data

physics-based model

artificial neural network


Input: We trained the SM and demonstrate its high predictive power and low computational cost.

SM

power


Input: With such performance, this model opens the possibility of optimization as well as process planning, and in situ monitoring for closed-loop control.

performance

model

optimization

in situ

as

as

planning

closed-loop control


Input: In the context of additive manufacturing, there is an exponential use of thermoplastic materials in the industrial and public open-source additive manufacturing sector, leading to an increase in global polymer consumption and waste generation.

additive manufacturing

additive manufacturing

thermoplastic materials

polymer

industrial

open-source


Input: However, the coupling of the open-source 3D printers with polymer processing could potentially offer the basis for a new paradigm of distributed recycling process.

open-source

recycling process

3D printers

polymer


Input: It could be a complementary alternative to the traditional paradigm of centralized recycling of polymers, which is often uneconomical and energy intensive due to transportation embodied energy.

be

polymers

recycling


Input: In order to achieve this goal, a first step is to prove the technical feasibility to recycle thermoplastic material intended for open-source 3D printing feedstock.The contribution of the present study is twofold: first, a general methodology to evaluate the recyclability of thermoplastics used as feedstock in open-source 3D printing machines is proposed.

step

feasibility

open-source

methodology

recyclability

open-source

thermoplastic material

thermoplastics

as

3D printing

3D printing


Input: Then, the proposed methodology is applied to the recycling study of polylactic acid (PLA) material addressed to the fused filament fabrication (FFF) technique, which is currently the most widely used.

methodology

recycling

polylactic acid

PLA

material

fused filament fabrication

FFF


Input: The main results of this application contribute to the understanding of the influence of the material's physico-chemical degradation on its mechanical properties as well as its potential distributed recyclability.

material

as

as

degradation

mechanical properties

recyclability


Input: Additively manufactured internal lattice structures offer a unique approach to lightweight components and adding multi-functionality.

Additively manufactured

lattice structures

lightweight

components


Input: Design methods for parts based on lattices are emerging and include a family of topology optimization schemes for tailoring local cell density to service loadings.

Design

topology optimization

cell density

lattices


Input: In order to gain confidence, these methods must be validated in a controlled manner.

gain

be


Input: In this paper, we report optimization, analysis, manufacturing, and mechanical test validation of a casing-like test article.

optimization

manufacturing

mechanical test


Input: The test article was optimized using a stress-based homogenized topology optimization approach and achieved a 53% weight reduction versus a solid, fully-dense casing with the same form factor.

homogenized

optimization

reduction

weight


Input: The optimized geometry was studied with high-fidelity finite element analysis and then additively manufactured.

geometry

high-fidelity finite element analysis

additively manufactured


Input: Mechanical testing was performed and demonstrated good correlation between the homogenized finite element model used for optimization, the high-fidelity finite element model, and experimental results.

Mechanical testing

homogenized

finite element model

optimization

high-fidelity finite element model

experimental


Input: The findings validate the optimization approach for the particular use and load case and start to build confidence in the approach as an accepted method.

optimization

build

as


Input: This work explores the feasibility of using the Abrasive Fluidized Bed (AFB) method to finish flat AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS).

feasibility

manufactured

Abrasive

Bed

Direct Metal Laser Sintering

DMLS


Input: Finishing was performed by rotating the substrates inside a fluidized bed of abrasives at high speeds.

Finishing

fluidized bed

abrasives


Input: The interaction between the fluidized abrasives and AlSi10Mg substrates has been investigated to analyze the influence of the operational parameters, namely, abrasive type and rotational speed, on the finishing performance.

abrasives

abrasive

parameters

finishing


Input: The morphological features of the substrates and geometrical tolerances have been inspected by field emission gun–scanning electron microscopy (FEG–SEM) and contact gauge profilometry.

tolerances

emission

electron microscopy

contact


Input: After short finishing cycles, the substrates featured a smoother surface morphology, while the edges were only influenced slightly by the abrasive impacts.

finishing

surface morphology

abrasive


Input: Abrasive Fluidized Bed (AFB) can therefore be considered a potential easy-to-automate, low cost, low time consuming and sustainable finishing technology for metal parts obtained through additive manufacturing.

Abrasive

be

metal

Bed

sustainable

finishing

additive manufacturing


Input: A texture prediction method was proposed for epitaxial columnar grains in SLM.

texture

prediction

epitaxial columnar grains

SLM


Input: The texture prediction method was combined with the melt pool prediction.

texture

prediction

melt pool


Input: Process and microstructure were linked quantitatively for the metal SLM AM process.

Process

microstructure

quantitatively

metal

AM process


Input: Texture evolution with the number of layers for SLM AlSi10Mg was simulated.

Texture

evolution

number of layers

SLM


Input: The simulated texture showed pattern and intensity similar to experiment results.

texture

pattern

experiment


Input: Metal additive manufacturing (AM) such as selective laser melting (SLM) has the powerful capability to produce very different microstructural features, hence different mechanical properties in metals using the same feedstock material but different values of process parameters.

Metal additive manufacturing

AM

SLM

as

metals

feedstock material

laser

microstructural

mechanical properties

process parameters


Input: The lack of a reliable theoretical model of the processing-microstructure relationship of AM material is preventing AM technology from being widely adopted by the manufacturing community.

theoretical model

AM material

AM technology

manufacturing


Input: Hence, the goal of this work is to establish the link between the microstructure (texture) and the process parameters (laser power, scanning speed, preheat and scanning strategy) of a metal SLM process.

microstructure

process parameters

scanning strategy

process

texture

laser power

scanning speed

metal


Input: To achieve the above goal, a quantitative semi-empirical method is proposed to predict the texture of the epitaxial columnar grains grown from polycrystal substrates.

quantitative

texture

epitaxial columnar grains


Input: Combined with the melt pool prediction by the Rosenthal solution, the processing and microstructure were linked together quantitatively.

melt pool

Rosenthal solution

microstructure

quantitatively


Input: The proposed method is used to estimate the texture evolution with the number of layers for EOS-DMLS-processed AlSi10Mg (unidirectional scanning direction in one layer and no rotation of scanning direction between layers).

texture

evolution

unidirectional scanning

scanning

number of layers

layer


Input: The texture reaches a steady state after five layers, and the steady state texture has similar pattern and intensity to that obtained from the experiment using the same process parameter values and scanning strategy.

texture

steady state

steady state

pattern

experiment

process parameter

scanning strategy


Input: The severe thermal gradients associated with selective laser melting (SLM) additive manufacturing (AM) generate large residual stresses (RS) that geometrically distort and otherwise alter the performance of printed parts.

thermal gradients

selective laser melting

SLM

additive manufacturing

AM

residual stresses

performance


Input: Despite broad research interest in this field, it has remained challenging to measure warpage in general as well as RS distributions in situ, which has obfuscated the mechanisms of stress formation during the printing process.

research

warpage

distributions

as

as

stress

printing process


Input: In pursuit of this goal, we have developed a non-destructive framework for RS measurement in SLM parts using three-dimensional digital image correlation (3D-DIC) to capture in situ surface distortion.

framework

three-dimensional

digital image correlation

in situ

distortion

RS measurement

SLM


Input: A two-dimensional analytical model was developed to convert DIC surface curvature measurements to estimates of in-plane residual stresses.

two-dimensional

model

DIC

residual stresses


Input: Experimental validation using stainless steel 316 L “inverted-cone” parts demonstrated that residual stress varied across the surface of the printed part, and strongly interacted with the component geometry.

Experimental

surface

stainless steel

residual stress

component


Input: The 3D-DIC based RS measurements were validated by X-ray diffraction (XRD), with an average error of 6% between measured and analytically derived stresses.

RS measurements

X-ray diffraction

XRD

average


Input: Systematic variation in RS was attributed to the sector-based laser raster strategy, which was supported by complementary finite element calculations.

variation

finite element

laser


Input: Calculations showed that the heterogeneous RS distribution in the parts emerged from the sequential re-heating and cooling of the new surface, and changed dynamically between layers.

heterogeneous

distribution

surface

cooling


Input: The unique DIC based RS methodology brings substantial benefits over alternatively proposed in situ AM RS measurements, and should facilitate enhanced process optimization and understanding leading towards AM part qualification.

DIC

methodology

in situ

process optimization

AM

AM part


Input: The interior porous defects formed during the layer-by-layer fabrication process have attracted increasing attention for different additive manufacturing (AM) techniques and are regarded as a crucial factor affecting the overall performance.

porous

defects

layer-by-layer

performance

fabrication

additive manufacturing

AM

as


Input: In this work, aiming at the cold spray Ti6Al4V bulk materials, the hot isostatic pressing (HIP) treatment is adopted to reduce the interior defects, adjust the microstructure, and improve the mechanical properties.

materials

defects

microstructure

mechanical properties

hot isostatic pressing

HIP


Input: To characterize the pore morphologies and porosity evolution, the CS Ti6Al4V sample is characterized by optical microscopy and X-ray computed tomography (XCT).

pore

porosity

morphologies

evolution

sample

optical microscopy

X-ray computed tomography


Input: The 3D reconstructions by XCT show that the fully dense Ti6Al4V alloy can be obtained through the high temperature diffusion and high pressure compacting of the HIP sample.

diffusion

pressure

fully dense

temperature

alloy

be

HIP


Input: After the HIP treatment, the severely deformed grains experience an obvious growth with the uniformly distributed β precipitates around equiaxed α grains.

HIP

deformed

precipitates

grains


Input: The tensile test shows that the strength of CS Ti6Al4V alloys can be largely improved by the enhanced diffusion and resultant metallurgical bonding.

tensile test

strength

Ti6Al4V alloys

be

diffusion

metallurgical bonding


Input: With the HIP treatment, the CS samples exhibit highly densified morphology and adjusted microstructure that can benefit the improvement of mechanical properties.

HIP

densified

samples

microstructure

mechanical properties


Input: A number of strategies that enable lattice structures to be derived from Topology Optimisation (TO) results suitable for Additive Manufacturing (AM) are presented.

lattice structures

Topology Optimisation

be

Additive Manufacturing

AM


Input: The proposed strategies are evaluated for mechanical performance and assessed for AM specific design related manufacturing considerations.

mechanical

AM

manufacturing

design


Input: Results from Finite Element (FE) analysis for the two loading scenarios considered: intended loading, and variability in loading, provide insight into the solution optimality and robustness of the design strategies.

Finite Element

variability

solution

FE

robustness

design


Input: Lattice strategies that capitalised on TO results were found to be considerably (∼40–50%) superior in terms of specific stiffness when compared to the structures where this was not the case.

Lattice

be

specific stiffness


Input: The Graded strategy was found to be the most desirable from both the design and manufacturing perspective.

be

design

manufacturing


Input: The presented pros-and-cons for the various proposed design strategies aim to provide insight into their suitability in meeting the challenges faced by the AM design community.

design

faced

AM


Input: Accompanying the increasing advances and interest in Additive Manufacturing (AM) technologies is an increasing demand for an industrial workforce that is knowledgeable about the technologies and how to apply them to solve real-world problems.

Additive Manufacturing

AM

technologies

technologies

industrial


Input: As a step towards addressing this knowledge gap, a workshop was held at the National Science Foundation (NSF) to discuss the educational needs to prepare industry for AM and its use in different fields.

As

step

industry

AM


Input: The workshop participants–66 representatives from academia, industry, and government–identified several key educational themes: (1) AM processes and process/material relationships, (2) engineering fundamentals with an emphasis on materials science and manufacturing, (3) professional skills for problem solving and critical thinking, (4) design practices and tools that leverage the design freedom enabled by AM, and (5) cross-functional teaming and ideation techniques to nurture creativity.

industry

engineering

AM processes

manufacturing

AM

materials

design freedom

design

tools


Input: First, ensure that all AM curricula provide students with an understanding of (i) AM and traditional manufacturing processes to enable them to effectively select the appropriate process for product realization; (ii) the relationships between AM processes and material properties; and (iii) “Design for AM”, including computational tools for AM design as well as frameworks for process selection, costing, and solution generation that take advantage of AM capabilities.

AM

AM

traditional manufacturing

AM processes

AM

AM

AM

processes

process

material properties

computational tools

process selection

solution

Design

as

as


Input: Second, establish a national network for AM education that, by leveraging existing “distributed” educational models and NSF’ s Advanced Technology Education (ATE) Programs, provides open source resources as well as packaged activities, courses, and curricula for all educational levels (K-Gray).

AM

s

as

as

Technology

source


Input: Fourth, provide support for collaborative and community-oriented maker spaces that promote awareness of AM among the public and provide AM training programs for incumbent workers in industry and students seeking alternative pathways to gain AM knowledge and experience.

support

industry

AM

AM

AM

gain


Input: The dynamic tensile properties of additively manufactured (AM) and cast Al-10Si-Mg alloy were investigated using high-speed synchrotron X-ray imaging coupled with a modified Kolsky bar apparatus.

dynamic

properties

additively manufactured

AM

cast

alloy

synchrotron

imaging


Input: A controlled tensile loading (strain rate ≈ 750 s−1) was applied using the Kolsky bar apparatus and the deformation and fracture behavior were recorded using the high-speed X-ray imaging setup.

tensile

strain rate

deformation

fracture

X-ray imaging


Input: The synchrotron X-ray computed tomography (CT) and high-speed imaging results worked together to identify the location of the critical flaw and to capture the dynamics of crack propagation.

synchrotron

CT

computed tomography

imaging

flaw

crack propagation


Input: In all experiments, the critical flaw was located on the surface of each specimen.

flaw

surface


Input: The AM specimens showed significantly higher crack propagation speed, yield strength, ultimate tensile strength, strain hardening coefficient, and yet lower ductility compared to the cast specimens under dynamic tension.

AM

strain hardening

cast

crack propagation

dynamic

yield strength

ultimate tensile strength

ductility


Input: Although the strength values were higher for the AM specimens, the critical mode I stress intensity factors were comparable for both specimens.

strength

stress

AM


Input: The microstructures of the samples were characterized by CT and scanning electron microcopy.

microstructures

samples

scanning

CT


Input: The correlation between the dynamic fracture behavior of the samples and the microstructure of the samples is analyzed and discussed.

dynamic

samples

microstructure

samples


Input: Additive manufacturing (AM) is uniquely suitable for healthcare applications due to its design flexibility and cost effectiveness for creating complex geometries.

Additive manufacturing

AM

design flexibility

effectiveness

complex geometries


Input: Successful arthroplasty requires integration of the prosthetic implant with the bone to replace the damaged joint.

prosthetic

implant

bone

joint


Input: Bone-mimetic biomaterials are utilised due to their mechanical properties and porous structure that allows bone ingrowth and implant fixation.

biomaterials

mechanical properties

bone ingrowth

porous

implant


Input: The predictability of predetermined interconnected porous structures produced by AM ensures the required shape, size and properties that are suitable for tissue ingrowth and prevention of the implant loosening.

porous

AM

properties

implant


Input: The quality of the manufacturing process needs to be established before the utilisation of the parts in healthcare.

quality

manufacturing process

be


Input: This paper demonstrates a novel examination method of acetabular hip prosthesis cups based on X-ray computed tomography (CT) and image processing.

hip prosthesis

X-ray computed tomography

CT

image


Input: The method was developed based on an innovative hip prosthesis acetabular cup prototype with a prescribed non-uniform lattice structure forming struts over the surface, with the interconnected porosity encouraging bone adhesion.

hip prosthesis

prototype

surface

lattice structure

forming

porosity

adhesion

bone


Input: This non-destructive, non-contact examination method can provide information of the interconnectivity of the porous structure, the standard deviation of the size of the pores and struts, the local thickness of the lattice structure in its size and spatial distribution.

porous

pores

standard deviation

spatial distribution

struts

lattice structure


Input: Fatigue limit of L-PBF maraging steels was characterized by infrared thermography.

Fatigue

L-PBF

steels

infrared


Input: Different manufacturing strategies led to varying fatigue limit values.

manufacturing

led

fatigue


Input: Printing process optimization with respect to fatigue performance can be envisaged.

Printing process

optimization

fatigue

be


Input: This paper deals with the fatigue performance of maraging steels manufactured by Powder Bed Fusion using a laser beam (L-PBF).

fatigue

maraging steels

manufactured

laser beam

Powder Bed Fusion

L-PBF


Input: The objective of the study was to develop a method for the rapid and reliable characterization of the produced material’ s fatigue limit using infrared (IR) thermography.

material

s

fatigue

infrared

IR


Input: Next, fatigue tests instrumented by IR camera were processed using heat source reconstruction to measure the mechanical dissipation due to fatigue damage.

fatigue tests

IR

camera

processed

heat source

mechanical

fatigue damage


Input: A statistical model was then proposed to identify the fatigue limit of the material.

model

fatigue

material


Input: Finally, a practical application was performed to compare different manufacturing strategies using the same powder, opening perspectives for the rapid optimization of the printing process with respect to the fatigue performance of the parts produced.

manufacturing

printing process

powder

optimization

fatigue


Input: Magnetically isotropic bonded magnets with a high loading fraction of 70 vol.% Nd-Fe-B are fabricated via an extrusion-based additive manufacturing, or 3D printing system that enables rapid production of large parts.

isotropic

magnets

fraction

fabricated

additive manufacturing

3D printing

production


Input: The density of the printed magnet is ∼ 5.2 g/cm3.

density

magnet


Input: The as-printed magnets are then coated with two types of polymers, both of which improve the thermal stability as revealed by flux aging loss measurements.

magnets

coated

polymers

as

flux

thermal stability


Input: Tensile tests performed at 25 °C and 100 °C show that the ultimate tensile stress (UTS) increases with increasing loading fraction of the magnet powder, and decreases with increasing temperature.

Tensile tests

tensile stress

UTS

fraction

magnet

temperature


Input: AC magnetic susceptibility and resistivity measurements show that the 3D printed Nd-Fe-B bonded magnets exhibit extremely low eddy current loss and high resistivity.

magnetic susceptibility

resistivity

resistivity

3D printed

magnets


Input: Finally, we demonstrate the performance of the 3D printed magnets in a DC motor configuration via back electromotive force measurements.

performance

configuration

force

3D printed

DC


Input: During solidification of many so-called high-performance engineering alloys, such as 6000 and 7000 series aluminum alloys, which are also unweldable autogenously, volumetric solidification shrinkage and thermal contraction produces voids and cracks.

solidification

solidification shrinkage

contraction

voids

engineering

alloys

as

aluminum alloys


Input: During additive manufacturing processing, these defects can span the length of columnar grains, as well as intergranular regions.

additive manufacturing

defects

columnar grains

as

as


Input: In this research, laser powder bed fusion (LPBF) of aluminum alloy (AA) 6061 used powder bed heating at 500 °C in combination with other experimentally determined processing parameters to produce crack-free components.

research

parameters

laser powder bed fusion

LPBF

heating

aluminum alloy

powder bed

components


Input: In addition, melt-pool banding, which is a normal solidification feature in LPBF, was eliminated, illustrating solidification process modification as a consequence of powder bed heating.

solidification

feature

LPBF

solidification process

heating

as

powder bed


Input: Corresponding microindentation hardness and tensile testing of the as-fabricated AA6061 components indicated an average Vickers hardness of HV 54, and tensile yield, ultimate strength, and elongation values of 60 MPa, 130 MPa, and 15%, respectively.

hardness

hardness

tensile

ultimate strength

elongation values

tensile testing

average

MPa

MPa


Input: These mechanical properties and those of heat treated parts showed values comparable to annealed and T6 heat treated wrought products, respectively.

mechanical properties

heat

heat

wrought


Input: X-ray diffraction and optical microscopy revealed columnar grain growth in the build direction with the as-fabricated, powder-bed heated product microstructure characterized by [100] textured, elongated grains (∼ 25 μm wide by 400 μm in length), and both intragranular and intergranular, noncoherent Al-Si-O precipitates which did not contribute significantly to the mechanical properties.

X-ray diffraction

optical microscopy

columnar grain

build direction

microstructure

grains

mechanical properties

precipitates


Input: The results of this study are indicative that powder bed heating may be used to assist with successful fabrication of AA6061 and other alloy systems susceptible to additive manufacturing solidification cracking.

powder bed

heating

fabrication

be

alloy

additive manufacturing solidification


Input: Recent developments in additive manufacturing (AM) technologies involving heat and mass deposition have exposed the need for computationally efficient modeling of thermal field histories.

additive manufacturing

AM

technologies

heat

deposition

modeling


Input: This is due to the effect of such histories on resulting morphologies and quantities of interest, such as micro- and meso-structure, residual strains and stresses, as well as on material and structural properties and associated functional performance at the macro-scale.

morphologies

residual

properties

performance

as

as

as

material


Input: Consequently, in this paper, analytic solutions are enriched and then used to model the thermal aspects of AM, in a manner that demonstrates both high computational performance and fidelity required to enable “in the loop” use for feedback control of AM processes.

model

performance

AM

AM processes

feedback


Input: It is first shown that the utility of existing analytical solutions is limited due to their underlying assumptions, some of which are their derivation based on a homogeneous semi-infinite domain and temperature independent material properties among others.

analytical solutions

homogeneous

domain

material properties

temperature


Input: These solutions must therefore be enriched in order to capture the actual thermal physics associated with the relevant AM processes.

be

physics

AM processes


Input: Enrichments introduced herein include the handling of strong nonlinear variations in material properties due to their dependence on temperature, finite non-convex solution domains, behavior of heat sources very near domain boundaries, and mass accretion coupled to the thermal problem.

variations

material properties

solution

heat sources

domain

temperature

boundaries


Input: Design for additive manufacturing (AM) requires knowledge of the constraints associated with your targeted AM process.

Design for additive manufacturing

AM

AM process


Input: One important design concern is the unintentional trapping of parasitic mass in occluded void geometries with either uncured or non-solidified material, or in some cases, sacrificial support material.

design

void geometries

material

support material


Input: These occluded features create the need to physically alter the optimal topology to remove the material.

topology

material


Input: In this work, a projection-based topology optimization design formulation is proposed to eliminate occluded void topological features in optimal AM designs.

topology optimization

design

void

AM


Input: The algorithm is based on the combination and enhancement of two existing algorithms: a projection-based, overhang-constrained algorithm to design self-supporting structures in AM, and a void projection algorithm to design topologies through control of the void phase.

algorithm

algorithms

algorithm

void

algorithm

void phase

design

design

AM


Input: The combined algorithm results in topologies with void regions that always possess an exit path to predefined outer surfaces–i.e.

algorithm

topologies

void

surfaces


Input: Solutions are first demonstrated in two dimensions, with increasing design freedom allowed through algorithm enhancements.

dimensions

design freedom

algorithm


Input: The algorithm is then adapted to 3D, adopting a multi-phase TO approach to not only regain control of the solid phase length scale, but also to drive toward superior performing topologies with minimal impact on the part performance.

algorithm

phase

topologies

impact

performance

length scale


Input: Steel–Inconel multi-scale multilayer by liquid metal dispersed powder bed fusion.

Steel

Inconel

liquid metal

powder bed fusion


Input: Nano-scale microstructural design by reactive additive manufacturing.

Nano-scale microstructural

design

additive manufacturing


Input: Gradients of microstructure, texture, residual stresses and chemical composition.

microstructure

chemical composition

texture

residual stresses


Input: Zig-zag columnar grains, grain boundaries and crack formation.

columnar grains

grain boundaries


Input: Multi-scale correlative characterization of additively manufactured gradient structures.

additively manufactured


Input: Synthesis of multi-metal hybrid structures with narrow heat affected zones, limited residual stresses and secondary phase occurrence represents a serious scientific and technological challenge.

heat affected zones

phase

residual stresses


Input: In this work, liquid dispersed metal powder bed fusion was used to additively manufacture a multilayered structure based on alternating Inconel 625 alloy (IN625) and 316L stainless steel (316L) layers on a 316L base plate.

metal powder bed fusion

additively manufacture

structure

Inconel 625 alloy

316L stainless steel


Input: Analytical scanning and transmission electron microscopies, high-energy synchrotron X-ray diffraction and nanoindentation analysis reveal sharp compositional, structural and microstructural boundaries between alternating 60 μm thick alloys’ sub-regions and unique microstructures at macro-, micro- and nano-scales.

scanning

microstructural

transmission electron microscopies

diffraction

nanoindentation

micro-

synchrotron

boundaries

nano-scales

alloys

microstructures


Input: The periodic occurrence of IN625 and 316L sub-regions is correlated with a cross-sectional hardness increase and decrease and compressive stress decrease and increase, respectively.

correlated

hardness

compressive stress


Input: The laser scanning strategy induced a growth of elongated grains separated by zig-zag low-angle grain boundaries, which correlate with the occurrence of zig-zag cracks propagating in the growth direction.

laser

grains

grain boundaries


Input: The occurrence of the C-like stress gradient with a pronounced surface tensile stress of about 500 MPa is interpreted by the temperature gradient mechanism model.

stress

stress

surface

MPa

temperature gradient mechanism

model


Input: Chemical analysis indicates a formation of reinforcing spherical chromium-metal-oxide nano-dispersoids and demonstrates a possibility for reactive additive manufacturing and microstructural design at the nanoscale, as a remarkable attribute of the deposition process.

Chemical analysis

spherical

microstructural

additive manufacturing

deposition process

design

as


Input: Finally, the study shows that the novel approach represents an effective tool to combine dissimilar metallic alloys into unique bionic hierarchical microstructures with possible synergetic properties.

tool

metallic alloys

microstructures

properties


Input: Binder jetting (BJ) is a high build-rate additive manufacturing process with growing commercial interest.

Binder jetting

BJ

additive manufacturing process


Input: Growth in BJ applications is driven by the use of finer powders and improved post-processing methods that can produce dense, homogenous final parts.

BJ

powders

post-processing


Input: This paper considers the impact of in-process drying, part geometry, and droplet size on a key printing parameter: binder saturation.

impact

geometry

parameter

drying

droplet size

binder


Input: Parts of varying thicknesses are printed with a range of saturation levels under various heating conditions.

range

heating


Input: In unheated powder beds, part mass increases linearly with printing saturation levels across the range tested (30% –130%).

powder beds

range


Input: However, when the powder is heated between layers, there is a wide range of print saturation levels (30–80%) over which increasing binder saturation or droplet volume does not increase the part mass.

powder

binder

range

print

droplet


Input: This stable part mass corresponds to accurate part geometries without bleeding and is likely due to enhanced evaporation of the binder solvent between layers.

accurate

geometries

evaporation

binder


Input: Smaller droplet volume (42 pl) was also shown to decrease saturation levels in unheated powder bed and in single layer parts.

droplet

pl

powder bed

layer


Input: The differences in part mass with print saturation and droplet volume are most pronounced in thin parts.

print

droplet


Input: These observations lead to a simple method for determining an appropriate print saturation parameter for a powder/binder combination in thick parts.

lead

simple

print

parameter


Input: Additive Manufacturing (AM) is widely gaining popularity as an alternative manufacturing technique for complex and customised parts.

Additive Manufacturing

AM

manufacturing

as


Input: AM materials are used for various medical applications in both metal and polymer options.

AM materials

metal

polymer

medical applications


Input: Adenosine Triphosphate (ATP) bioluminescence technology is a rapid, user-friendly method of quantifying surface cleanliness and was used in this study to gather quantitative data on levels of contamination on AM materials at three different stage processes: post build, post cleaning and post sterilization.

technology

surface

quantitative data

processes

AM materials

build

cleaning


Input: The surface cleanliness of eleven AM materials, three metals and eight polymers, was tested.

surface

AM materials

metals

polymers


Input: ATP bioluminescence provided the sensitivity to evaluate different material surface characteristics, and specifically the impact of surface finishing techniques on overall cleanliness.

sensitivity

material

impact

surface finishing


Input: Selective laser melting (SLM) provides flexibility in creating novel metal-matrix composites (MMCs) with unique microstructures and enhanced mechanical properties over conventionally manufactured MMGs.

Selective laser melting

SLM

flexibility

composites

MMCs

microstructures

mechanical properties

manufactured


Input: In this study, a Zr-based metallic glass (MG) decorated Ti6Al4V (Ti64) composite with a unique hybrid nanostructure and enhanced mechanical properties and wear resistance was fabricated using SLM.

metallic glass

MG

composite

mechanical properties

fabricated

wear resistance

SLM


Input: The results revealed that a near-full dense and crack-free Ti-based composite was produced, with its reinforcements consisting of ultrafine β dendrites set with partially crystallized MG nanobands uniformly distributed along the boundaries of the melt pool.

composite

MG

melt pool

dendrites

boundaries


Input: The addition of MG significantly affected the solidification behavior of the Ti-liquid because of its higher dynamic viscosity and density as well as compositional effect on the phase stability.

MG

as

as

solidification

dynamic

phase

density


Input: With such a unique nanostructured reinforcement, the Ti64/MG composite exhibited an enhanced yield strength (> 1 GPa) with reasonable ductility and fracture toughness.

reinforcement

composite

yield strength

GPa

ductility

fracture


Input: On the basis of the result of a theoretical analysis, we attributed the main strengthening mechanism to Orowan strengthening.

theoretical

strengthening mechanism

strengthening


Input: The wear resistance was also much improved in the Ti64/MG composite, arising from the higher hardness of the nanostructured reinforcement and the formation of a more protective tribo-oxide layer during sliding.

wear resistance

hardness

composite

reinforcement

layer


Input: The confinement of the 3D distributed reinforcement phase played a crucial role in preventing the delamination of the tribo-layer on the matrix.

phase

delamination

reinforcement


Input: This work opens a pathway to the design of novel additively manufactured MMCs with outstanding mechanical properties.

design

additively manufactured

mechanical properties


Input: Fatigue of laser beam powder bed fused (LB-PBF) 316 L stainless steel is investigated.

Fatigue

laser beam

bed

stainless steel


Input: Effects of build orientation and surface roughness are examined.

build orientation

surface roughness


Input: Fractography and failure analysis on fatigue specimens are conducted.

Fractography

failure

fatigue


Input: A fracture mechanics-based approach is employed to explain the fatigue results.

fracture

fatigue


Input: The effects of layer orientation and surface roughness on the mechanical properties and fatigue life of 316L stainless steel (SS) fabricated via a laser beam powder bed fusion (LB-PBF) additive manufacturing process were investigated.

layer

surface roughness

fatigue life

mechanical properties

fabricated

laser beam

316L stainless steel

SS

bed fusion

additive manufacturing process


Input: Quasi-static tensile and uniaxial fatigue tests were conducted on LB-PBF 316L SS specimens fabricated in vertical and diagonal directions in their as-built surface condition, as well as in horizontal, vertical, and diagonal directions where the surface had been machined to remove any effects of surface roughness.

Quasi-static

fabricated

vertical

surface

vertical

surface

fatigue tests

SS

as

as

machined

surface roughness


Input: Similarly, in the as-built condition, vertical specimens demonstrated better fatigue resistance when compared to diagonal specimens.

vertical

fatigue


Input: Furthermore, the detrimental effects of surface roughness on fatigue life of LB-PBF 316L SS specimens was not significant, which may be due to the presence of large internal defects in the specimens.

surface roughness

fatigue life

SS

be

defects


Input: Anisotropy of LB-PBF 316L SS specimens was attributed to the variation in layer orientation, affecting defects’ directionality with respect to the loading direction.

Anisotropy

SS

variation

defects

layer


Input: These defect characteristics can significantly influence the stress concentration and, consequently, fatigue behavior of additive manufactured parts.

defect

stress concentration

fatigue

additive manufactured parts


Input: Therefore, the elastic-plastic energy release rates, a fracture mechanics-based concept that incorporates size, location, and projected area of defects on the loading plane, were determined to correlate the fatigue data and acceptable results were achieved.

fracture

defects

data

area

fatigue


Input: As-built microstructure of L-PBF AM consists of fine dendrites and precipitates.

microstructure

L-PBF AM

dendrites

precipitates


Input: Precipitates comprise mostly Laves phase and small amount of NbC carbide.

Precipitates

carbide

Laves phase


Input: Uniformly distributed hardness for samples built with and without support.

hardness

samples

support


Input: Calculations show heat build-up of 487 K with support versus 353 K without support.

heat

K

K

support

support


Input: Solidification cooling rate 6.57 × 105 K/s with support versus 8.45 × 105 K/s without.

Solidification cooling rate

support


Input: INCONEL® 718 cubes with and without structural support were built by laser-powder bed fusion (L-PBF) additive manufacturing.

support

bed fusion

L-PBF

additive manufacturing


Input: The effect of support on the as-built microstructure was studied based on the microstructural characteristics and micro-hardness variations.

support

microstructure

microstructural

variations


Input: Specifically, the microstructure was examined by optical microscopy, and scanning and transmission electron microscopy.

microstructure

scanning

optical microscopy

transmission electron microscopy


Input: The precipitates were identified via selected area diffraction supplemented by high-resolution energy dispersive X-ray spectroscopy.

precipitates

area

high-resolution

energy dispersive X-ray spectroscopy


Input: Micro-hardness distributions on cross sections parallel and perpendicular to the build direction were mapped.

distributions

cross sections

build direction


Input: In addition, analytical equations, taking into account various laser processing parameters, material properties and support geometries, were developed to calculate the heat build-up and cooling conditions during L-PBF.

laser processing

material properties

geometries

heat

support

cooling

L-PBF


Input: The results of microstructure characterization and analytical calculation showed a marginal effect of the support on the local microstructure and hardness due to the low heat input in L-PBF.

microstructure

microstructure

heat

support

hardness

L-PBF


Input: Moreover, the comprehensive set of microstructure data is useful for future work of modelling processing-microstructure relation as well as optimizing post-fabrication heat treatment.

set

microstructure data

modelling

as

as

heat treatment


Input: The ability to simulate the thermal, mechanical, and material response in additive manufacturing offers tremendous utility for gaining a deeper understanding of the process, while also having significant practical application.

mechanical

material

additive manufacturing

process


Input: The approach and progress in establishing an integrated computational system for simulating additive manufacturing of metallic components are discussed, with the primary focus directed at the computational intensive components, which include the process and material models.

additive manufacturing

metallic

material

components

components

process


Input: SRAS optical data was used for defect characterisation of an SLM layer.

optical

data

defect

SLM

layer


Input: A bespoke algorithm was developed to target defects for rework.

algorithm

defects


Input: A hatch pattern rework showed to be the most effective method for rework.

pattern

be


Input: A general framework for targeted rework in AM processes is presented.

framework

AM processes


Input: A major factor limiting the adoption of powder-bed-fusion additive manufacturing for production of parts is the control of build process defects and the effect these have upon the certification of parts for structural applications.

additive manufacturing

production

build

defects


Input: In response to this, new methods for detecting defects and to monitor process performance are being developed.

defects

monitor

performance


Input: However, effective utilisation of such methods to rework parts in process has yet to be demonstrated.This study investigates the use of spatially resolved acoustic spectroscopy (SRAS) scan data to inform repair strategies within a commercial selective laser melting machine.

process

investigates

spectroscopy

data

be

selective laser melting

machine


Input: New methodologies which allow for rework of the most common defects observed in selective laser melting (SLM) manufacturing are proposed and demonstrated.

defects

selective laser melting

SLM

manufacturing


Input: Three rework methodologies are applied to targeted surface breaking pores: a hatch pattern, a spiral pattern and a single shot exposure.

surface

pattern

pattern

exposure

pores


Input: The work presented shows that it is possible to correct surface breaking pores using targeted re-melting, reducing the depth of defects whilst minimising changes in local texture.

surface

defects

pores

texture


Input: This work is part of a programme to develop a method by which defects can be detected and the part reworked in-process during SLM to enable defect specification targets to be met.

defects

defect

be

be

SLM


Input: Despite the rapid adoption of laser powder bed fusion (LPBF) Additive Manufacturing by industry, current processes remain largely open-loop, with limited real-time monitoring capabilities.

laser powder bed fusion

LPBF

Additive Manufacturing

industry

processes


Input: While some machines offer powder bed visualization during builds, they lack automated analysis capability.

machines

powder bed

builds


Input: This work presents an approach for in-situ monitoring and analysis of powder bed images with the potential to become a component of a real-time control system in an LPBF machine.

in-situ

images

powder bed

component

control system

LPBF


Input: Specifically, a computer vision algorithm is used to automatically detect and classify anomalies that occur during the powder spreading stage of the process.

computer vision algorithm

anomalies

process

powder


Input: Anomaly detection and classification are implemented using an unsupervised machine learning algorithm, operating on a moderately-sized training database of image patches.

Anomaly

classification

image

machine learning algorithm

database


Input: The performance of the final algorithm is evaluated, and its usefulness as a standalone software package is demonstrated with several case studies.

performance

algorithm

software

case studies

as


Input: The mechanical, metallurgical and corrosion properties of Alloy 625 produced using the laser powder bed fusion (L-PBF) manufacturing process were investigated and compared with typical performance of the alloy produced using conventional forging processes.

mechanical

metallurgical

corrosion properties

Alloy

alloy

laser powder bed fusion

L-PBF

manufacturing process

forging

performance


Input: Test specimens were produced near net shape along with several demonstration pieces that were produced to examine the geometric complexity that could be achieved with the process.

near net shape

complexity

process

be


Input: The additively manufactured specimens exhibited strength, fracture toughness and impact toughness that was equal to or better than properties typically achieved for wrought product.

additively manufactured

strength

fracture

impact

properties

wrought


Input: There was no evidence of stress corrosion cracking susceptibility in 3.5% NaCl solution at stress intensities up to 70 ksi-in1/2 after 700 h exposure.

stress corrosion cracking

exposure

NaCl

stress


Input: The microstructure was equiaxed in the plane of the powder bed build platform (X–Y) and exhibited a columnar shape in the Z direction although there was not any significant evidence of anisotropy in the mechanical properties.

microstructure

mechanical properties

powder bed build platform

anisotropy


Input: The high hardness, melting temperature and environmental resistance of most ceramic materials makes them well-suited for propulsion, tribilogical and protective applications.

hardness

resistance

melting temperature

ceramic materials


Input: However, these same attributes pose difficulties for manufacturing and machining of ceramics and ultimately limit the achievable design space of these materials.

manufacturing

machining

ceramics

limit

design space

materials


Input: Recently, a new class of preceramic photopolymers has been developed that enables additive manufacturing of ceramics using commercially available stereolithography systems.

photopolymers

ceramics

additive manufacturing

stereolithography


Input: By consolidating preceramic monomers via layer-wise exposure to ultraviolet light and subsequently pyrolyzing under an inert atmosphere to form a ceramic, this method allows for complex geometry parts that can not be produced with traditional sintering, pressing or vapor infiltration processes.

exposure

ultraviolet light

complex geometry

infiltration

ceramic

be

sintering

pressing


Input: To this end, we present x-ray micro-computed tomography (micro-CT) measurements of the dimensional stability and uniformity of additively manufactured silicon-based ceramics as a function of geometry and processing conditions.

x-ray micro-computed tomography

micro-CT

stability

additively manufactured

ceramics

as

geometry


Input: Laser polishing (LP) is an emerging technique with the potential to be used for post-build, or in-situ, precision smoothing of rough, fatigue-initiation prone, surfaces of additive manufactured (AM) components.

Laser

be

in-situ

surfaces

precision

additive manufactured

AM

components


Input: LP uses a laser to re-melt a thin surface layer and smooths the surface by exploiting surface tension effects in the melt pool.

laser

surface

surface

layer

surface tension

melt pool


Input: However, rapid re-solidification of the melted surface layer and the associated substrate thermal exposure can significantly modify the subsurface material.

melted

exposure

layer

substrate

material


Input: This study has used an electron beam melted (EBM) Ti6Al4V component, representing the worst case scenario in terms of roughness for a powder bed process, as an example to investigate these issues and evaluate the capability of the LP technique for improving the surface quality of AM parts.

electron beam

EBM

as

component

powder bed

AM parts

roughness

surface quality


Input: Experiments have shown that the surface roughness can be reduced to below Sa = 0.51 μm, which is comparable to a CNC machined surface, and high stress concentrating defects inherited from the AM process were removed by LP.

surface roughness

stress

be

CNC

surface

defects

AM process


Input: However, the re-melted layer underwent a change in texture, grain structure, and a martensitic transformation, which was subsequently tempered in-situ by repeated beam rastering and resulted in a small increase in sub-surface hardness.

layer

texture

grain structure

in-situ

tempered

beam

hardness


Input: In addition, a high level of near-surface tensile residual stresses was generated by the process, although they could be relaxed to near zero by a standard stress relief heat treatment.

tensile residual stresses

process

standard

be

heat treatment


Input: Currently, additive manufacturing is a rapidly growing technique that should be explored for the development of various composites and alloys.

additive manufacturing

be

composites

alloys


Input: Graphene is also simultaneously gaining considerable attention as a reinforcement material for metals due to its superior properties.

Graphene

as

material

metals

reinforcement

properties


Input: In this study, a graphene/AlSi10Mg composite was developed using the powder bed fusion (PBF) technique.

composite

powder bed fusion

PBF


Input: The effect of graphene reinforcement and laser power variation was studied on the basis of the porosity, microstructure and mechanical properties of the composite.

graphene

composite

laser power

porosity

microstructure

mechanical properties


Input: First, graphene (0.1 and 0.2 wt.%) was mixed in AlSi10Mg powder by conducting low-energy ball milling.

graphene

ball milling


Input: The resultant mixture was used for PBF at laser power values of 200, 300 and 400 W. The prepared samples were characterised by synchrotron-based X-ray computed tomography to observe their pore distribution and morphology.

PBF

laser power

samples

distribution

morphology

X-ray computed tomography

pore


Input: The observation results reveal that the energy (laser power) required for appropriate melting of the powder was increased after graphene incorporation.

laser power

melting

powder

graphene


Input: Electron backscattered diffraction analysis revealed grain refinement and increase in fraction of high angle grain boundaries due to progressive addition of graphene.

diffraction

grain refinement

fraction

grain boundaries

graphene


Input: The strain developed after graphene incorporation was also validated using X-ray diffraction analysis.

strain

graphene

X-ray diffraction analysis


Input: The uniform distribution of graphene and its structural inherency was confirmed by Raman analysis.

distribution

graphene

Raman analysis


Input: Moreover, transmission electron microscopy revealed a suitable graphene-matrix interface.

transmission electron microscopy

interface


Input: The tensile properties were significantly influenced by the porosity induced in the samples irrespective of graphene reinforcement.

tensile properties

porosity

samples

graphene


Input: However, a yield strength increase of 22% was observed in the composite compared with the strength of unreinforced sample of equivalent density.

yield strength

strength

density

composite

sample


Input: Hardness increased progressively with the graphene content and was unaffected by variation in the laser power.

Hardness

graphene

variation

laser power


Input: Material jetting 3D printing is an additive manufacturing technique that allows producing complex parts without tooling and minimum material wastage.

Material jetting 3D printing

additive manufacturing

tooling

material


Input: In this study, orientation control of randomly shaped, anisotropic hard magnetic ferrite particles is demonstrated for material jetting-based additive manufacturing processes using a developed particle alignment configuration.

orientation

particle

configuration

anisotropic

ferrite

material

additive manufacturing processes


Input: Strontium ferrite and PR-48 photosensitive resin were used as the base materials.

ferrite

photosensitive resin

as

materials


Input: An automated experimental setup with two neodymium permanent cube magnets capable of generating a dipolar magnetic field was built to align magnetic particles in the resin.

experimental

cube

magnetic field

particles

neodymium

resin


Input: Particle alignment was characterized for directionality using images obtained through real time optical microscopy.

Particle

images

optical microscopy


Input: The orientation of magnetic particles was observed to be dependent on the distance of separation between the cube magnets and the magnetization time.

orientation

particles

cube

be


Input: X-ray diffraction was used to indicate the c-axis alignment of the hexagonal strontium ferrite particles in the cured specimens.

X-ray diffraction

hexagonal

ferrite

cured


Input: The influence of process parameters on particle orientation was evaluated, employing a full factorial experiment analysis.

process parameters

particle

orientation

experiment


Input: This fundamental research serves as a basis for constructing and optimizing the magnetic particle alignment setup for additive manufacturing processes.

research

particle

as

additive manufacturing processes


Input: Measurements of the temperature and distortion evolution during laser powder bed fusion (LPBF) are taken as a function of time.

temperature

distortion

laser powder bed fusion

LPBF

as


Input: In situ measurements have proven vital to the development and validation of FE (finite element) models for alternate forms of additive manufacturing.

In situ

validation

finite element

FE

additive manufacturing


Input: Due to powder obscuring all but the top layer of the part in LPBF, many non-contact measurement techniques used for in situ measurement of additive manufacturing processes are impossible.

powder

layer

LPBF

additive manufacturing processes

measurement

in situ


Input: Therefore, an enclosed instrumented system is designed to allow for the in situ measurement of temperature and distortion in an LPBF machine without the need for altering the machine or the build process.

designed

in situ

distortion

temperature

build

LPBF

machine


Input: By instrumenting a substrate from underneath, the spread powder does not affect measurements.

substrate

powder

spread


Input: Default processing parameters for the EOS M280 machine prescribe a rotating scan pattern of 67° for each layer.

parameters

EOS

machine

scan pattern

layer


Input: One test is completed using the default rotating scan pattern and a second is completed using a constant scan pattern.

scan pattern

scan pattern


Input: Experimental observations for the build geometry tested showed that for Inconel® 718 and a constant scan pattern produce results in a 37.6% increase in distortion as compared with a rotated scan pattern.

Experimental

distortion

build

scan pattern

scan pattern

as


Input: The in situ measurements also show that the thermal cycles caused by the processing of a layer can impact the distortion accumulated during the deposition of the previous layers.

in situ

impact

distortion

deposition

thermal cycles

layer


Input: The amount of distortion built per layer between the rotating and constant scan pattern cases highlights inter-layer effects not previously discovered in LPBF.

distortion

layer

scan pattern

LPBF


Input: The demonstrated inter-layer effects in the LPBF process should be considered in the development of thermo-mechanical models of the LPBF process.

LPBF

LPBF

be

thermo-mechanical models


Input: Increasing demand for high-quality additive manufactured parts in the aerospace, automotive, medical, and oil and gas industries requires careful control of the part microstructure, residual stress, and density homogeneity.

additive manufactured parts

aerospace

automotive

medical

oil

gas

microstructure

residual stress

density


Input: In order to improve part quality, partial remelting of the as-built material during subsequent beam scans is desirable.

quality

material

beam


Input: Here, we make use of computer simulations to explicitly study remelting in laser- or electron beam-melting additive manufacturing.

computer simulations

additive manufacturing


Input: By explicitly implementing phase transformations between the powder, the liquid, and the bulk, we track the amount of material that is subject to remelting.

phase

powder

material


Input: The influence of the beam parameters, such as the beam size, scan speed and power, are investigated and both the cases of an exponential as well as a linear beam absorption profile are considered.

beam

beam

beam

as

as

as

scan speed

power

absorption


Input: We find that, at constant beam cross section, there is an optimal beam shape for remelting.

beam

beam


Input: Calculations are presented for the model case of AISI 316L stainless steel but can be extended to a wide class of metals.

model

316L stainless steel

be

metals


Input: Binder jetting technology enables the production of sand casting molds and cores without a pattern.

Binder jetting

production

sand casting

molds

cores

pattern


Input: Real-time inertial measurement is demonstrated with encapsulated wireless sensors in sand cores.

measurement

encapsulated

sensors

cores

sand


Input: In this work, real-time in-process monitoring of core motion in metal castings is demonstrated through the use of two emerging technologies.

core

metal

technologies


Input: 3D sand printing (3DSP) is a binder jetting additive manufacturing process that is quickly manifesting itself as a technological disrupter in the metal casting industry.

binder jetting additive manufacturing

casting

as

metal


Input: Based on its direct digital manufacturing principle, 3DSP enables complex mold and core design freedom that has been previously unavailable to foundry engineers.

direct digital manufacturing

foundry

mold

core


Input: In addition, the miniaturization and affordability of electronics and sensing equipment is rapidly accelerating.

electronics

sensing

equipment


Input: An experimental casting and mold were designed in this research to demonstrate and evaluate wireless sensing of core shifts.

experimental

research

casting

mold

core

designed

sensing


Input: With the use of 3D sand printing, precisely sized and located pockets were manufactured inside of cores.

manufactured

cores


Input: Miniature wireless Bluetooth sensors capable of measuring acceleration and rotation were then embedded inside the cores.

sensors

cores


Input: From these, high fidelity data were captured wirelessly from the sensors during the casting process.

data

sensors

casting


Input: With strategically designed core prints designed to allow varying levels of core motion, it is shown that core shifts can be measured and discriminated during casting in real time.

designed

core prints

core

core

be

casting


Input: The fracture properties (stress intensity factor and energy release rate) of additively manufactured (AM) polylactic acid (PLA) and its short carbon fiber (CF) reinforced composites have been studied.

fracture

reinforced

stress

additively manufactured

AM

polylactic acid

PLA

short carbon fiber

composites


Input: The effects of CF reinforcement, nozzle geometry and bead lay-up orientations in fracture properties, void contents, and interfacial bonding were investigated.

reinforcement

nozzle

geometry

orientations

fracture

void

interfacial bonding

bead


Input: The fused filament fabrication (FFF) -based AM specimens using both circular and square shaped nozzle were printed and compared with the conventional compression molded (CM) samples.

fused filament fabrication

FFF

AM

nozzle

compression

samples


Input: Compact tension (CT) specimens with different CF concentrations (0 wt.%, 3 wt.

Compact

CT


Input: %, 5 wt.%, 7 wt.% and 10 wt.%) were printed with two bead lay-up orientations (450/-450 and 00/900) using PLA and CF/PLA composite filaments.

bead

orientations

PLA

composite


Input: The results show significant improvement in fracture toughness and fracture energy for CF/PLA composites in comparison to neat PLA.

fracture

fracture

composites

PLA


Input: The increase in fracture energy was observed to be about 77% for 00/900 and 88% for 450/-450 bead orientations, respectively for the same fiber reinforcement (5 wt.

fracture

be

bead

fiber reinforcement


Input: Such improvement in fracture properties is expected to be higher for all 900 bead orientations.

fracture

be

bead


Input: The samples printed by square-shaped nozzle showed enhanced fracture toughness with less inter-bead voids and larger bonded areas in comparison to the circular-shaped nozzle.

samples

fracture

voids

nozzle

nozzle

areas


Input: Although the fracture toughness showed very negligible differences between 00/900 and 450/-450 specimens, distinguishable variation may be seen in the case of 00 and 900 bead orientations.

fracture

variation

be

bead


Input: The crack propagation path and fracture mechanisms were studied using optical microscopy (OM) and scanning electron microscopy (SEM) examinations.

crack propagation

fracture

optical microscopy

OM

scanning electron microscopy

SEM


Input: Fractography revealed different modes of failure with a very high fiber orientation along the printing direction and a relatively higher void contents for 7 and 10 wt.

Fractography

failure

void

fiber orientation


Input: % fiber reinforcement.

fiber reinforcement


Input: The advent of additive manufacturing (AM), also often referred to as 3D printing, has enabled the rapid production of parts with complex geometries that are either labor-intensive or unrealizable by traditional manufacturing methods.

additive manufacturing

AM

3D printing

production

traditional manufacturing

as

complex geometries


Input: Many existing 3D printing technologies, however, only allow one material to be printed at one time, while many applications require the integration of different materials, which sometimes can not be printed by one AM technology.

3D printing technologies

material

be

be

materials

AM technology


Input: In this paper, a novel multi-material multi-method (m4) 3D printer comprised of multiple AM technologies is presented as a solution to the current limitations.

multi-material

solution

AM technologies

3D printer

as


Input: This printer fosters the advancement of AM by combining materials traditionally unable to be printed concurrently while adding functionality to printed parts.

printer

AM

materials

be


Input: The m4 3D printer integrates four AM technologies and two complementary technologies onto one single platform, including inkjet (IJ), fused filament fabrication (FFF), direct ink writing (DIW), and aerosol jetting (AJ), along with robotic arms for pick-and-place (PnP) and photonic curing for intense pulsed light (IPL) sintering.

AM technologies

inkjet

fused filament fabrication

FFF

DIW

jetting

curing

sintering

3D printer

platform

robotic arms

technologies

ink


Input: The integration of these AM technologies and PnP into a single platform allows for rapid fabrication of complex devices, providing a wide range of functionalities with applications ranging from soft robotics and flexible electronics to medical devices.

AM technologies

rapid fabrication

platform

range

soft robotics

medical devices

electronics


Input: Magnesium alloys are highly attractive in aerospace and auto industries due to their high strength-to-weight ratio.

Magnesium alloys

aerospace

industries


Input: Additive manufacturing of Mg alloys can further save cost from materials and machining time.

Additive manufacturing

machining

Mg alloys

materials


Input: This paper investigates the microstructure and dynamic mechanical behavior of WE-43 Mg alloy built through the powder bed fusion process.

investigates

microstructure

dynamic

Mg alloy

powder bed fusion process


Input: Samples from four different combinations of processing parameters were built.

Samples

parameters


Input: These builds were studied in both as-built and hot isostatically pressed conditions.

builds

pressed


Input: The resultant complex microstructures were studied under scanning and transmission electron microscopes while their dynamic mechanical behavior was evaluated using a split-Hopkinson pressure bar testing system.

microstructures

scanning

dynamic

pressure

transmission electron microscopes

testing


Input: Effects of initial porosity and microstructural evolution during HIP treatment on mechanical response are discussed.

porosity

microstructural evolution

mechanical response

HIP


Input: Any literature investigation of Laser Powder Bed Fusion (L-PBF) manufacturing of metal parts would reveal that the development of internal stresses is a serious limitation in the application of this technology.

Laser Powder Bed Fusion

L-PBF

manufacturing

metal

internal stresses

technology


Input: Researchers have used a variety of different methods to quantify this stress and investigate scanning strategies aimed at reducing or distributing this stress more evenly in the part.

stress

stress

scanning strategies


Input: These techniques provide a rapid method to give a quantitative comparison of scan strategies and parameters.

quantitative

parameters


Input: Non-destructive diffraction based methods can be used to calculate the profile of stress in a part but these are often prohibitively expensive or difficult to use on a large scale.

diffraction

be

profile

stress


Input: This study presents a methodology which combines deflection based methods with either the hole drilling or contour methods.

methodology

hole drilling

contour


Input: Results show that these experiments can be completed in a cost effective manner, with standard lab based equipment to generate a through thickness measurement of residual stress.

be

standard

equipment

measurement

residual stress


Input: To benefit from the fascinating properties of multi-material structures, the interfacial joint should exhibit good mechanical strength.

properties

joint

multi-material structures

mechanical strength


Input: Evaluating the shear strength of a bimetallic joint via conventional methods is usually complex, and in most cases produces unreliable data due to induced bending stress among others.

shear strength

joint

data

bending


Input: In this work, a novel single-shear test device was designed and fabricated to measure shear strength of bimetallic joints.

designed

fabricated

shear strength


Input: The device was first standardized by shearing standard materials, and the results were in good agreement with published data.

shearing

materials

data


Input: Subsequently, the shear strength of Inconel 718/copper alloy (GRCop-84) bimetallic joint built via laser engineered net shaping (LENS™) was evaluated.

shear strength

Inconel

alloy

joint

laser engineered net shaping


Input: Compression test on the bimetallic joint was carried out as well for more mechanical characterization.

Compression test

joint

as

mechanical


Input: Both shear and compressive yield strengths of the bimetallic joints were compared with the base materials in addition to influence of thermal cycling on the joint strength.

yield strengths

materials

joint

thermal cycling


Input: Inconel 718/GRCop-84 bimetallic-joint shear strength was 220 ± 18 MPa and 231 ± 27 MPa for as-printed sample and after thermal cycling, respectively.

Inconel

shear strength

MPa

MPa

sample

thermal cycling


Input: Likewise, the bimetallic yield strength after compression test was 232 ± 3 MPa and 337 ± 15 MPa.

yield strength

compression test

MPa

MPa


Input: No cracking through or along the interface was observed even after thermal cycling, which indicates no thermal degradation at the bimetallic interfacial joint.

cracking

interface

degradation

joint

thermal cycling


Input: Increase in compressive yield strength after thermal cycling could be attributed to precipitation of Cr2Nb particles in GRCop-84 matrix along with strengthening due to gamma phases in Inconel 718.

yield strength

thermal cycling

be

Inconel 718

precipitation

particles

strengthening


Input: Scanning electron microscopy (SEM) and backscatter electron imaging were used to examine the interfacial microstructures and failure modes.

Scanning electron microscopy

SEM

imaging

microstructures

failure modes


Input: EDS was used as well to analyze the interface elemental composition.

EDS

as

interface

composition


Input: The development of the single-shear test device can provide an added opportunity to effectively evaluate mechanical behavior, reliability and performance of additively manufactured multi-material structures through bond strength analysis.

mechanical

reliability

performance

bond strength

additively manufactured


Input: In this work, we develop a simple model to determine the upper bound of feed rates that do not cause jamming in material extrusion additive manufacturing, also known as fused deposition modeling (FDM) ™ or fused-filament fabrication (FFF).

simple

material extrusion additive manufacturing

FDM

fused-filament fabrication

FFF

model

deposition modeling

feed

as


Input: We first derive a relation between the tube temperature and Péclet number for the solid portion of polymer filaments.

temperature

polymer filaments


Input: We focus on the boundary between the solid and molten polymer in the heated portion of the tube.

boundary

polymer


Input: We find the Péclet number that corresponds to the point at which this boundary makes contact with the nozzle, and identify this as the upper bound of the feed rate.

boundary

contact

nozzle

as

feed


Input: We compare our predictions to experimental results.

predictions

experimental


Input: We find good agreement for tube temperatures sufficiently above the glass-transition temperature, which is the temperature region of typical additive manufacturing.

temperatures

temperature

temperature

additive manufacturing


Input: Additive manufacturing potential of cold spray technology was used to fabricate freestanding samples of a copper alloy.

Additive manufacturing

fabricate

technology

samples

copper alloy


Input: Different volume fractions of micro and nanocrystalline powder particles were used to obatin a bimodal structure with heterogeneous arrangement of crystalline phases.

volume fractions

powder particles

structure

heterogeneous


Input: The effects of volume fractions of each phase were investigated on the microstructural arrangement, porosity, microhardness, residual stresses, and mechanical strength of the deposited materials.

volume fractions

phase

microstructural

microhardness

materials

porosity

residual stresses

mechanical strength


Input: A series of finite element simulations were developed and validated by experimental data to describe the influence of volume fraction, morphology, and spatial distribution of the phases on the global strength of the samples under tensile loading.

finite element

experimental data

morphology

samples

volume fraction

spatial distribution

strength

tensile


Input: The obtained results evidence the possibility of tailoring the mechanical response of freestanding cold spray deposits, adopting a heterogeneous phase structure.

mechanical response

heterogeneous

structure


Input: Optimized fabrication parameters and post-processing strategies should be studied to further enhance the performance of the designed bimodal materials and overcome the intrinsic brittleness of cold spray deposits.

fabrication

post-processing

performance

materials

be

designed


Input: In this article, we propose a model that can account for the effect of porosity and high surface roughness on the fatigue crack initiation of AM Ti6Al4V alloys in moderate and high cycle fatigue regimes.

model

porosity

surface roughness

fatigue

fatigue

AM

alloys


Input: Within these fatigue regimes, the applied force to the component is below the yield stress, however, defective features, viz., porosity and high surface roughness, can act as stress raisers.

fatigue

yield stress

porosity

surface roughness

force

component

as


Input: As a consequence, local plasticity can occur.

As

plasticity


Input: To capture this phenomenon, a nonlinear isotropic kinematic hardening elasto-plasticity model is employed in our finite element (FE) model.

isotropic

hardening

model

finite element

model

FE


Input: For creating the geometry of the FE models, inputs from fractography analyses and surface roughness measurements are needed.

geometry

FE

fractography

surface roughness


Input: From fractography analyses, the shape of pores formed by gas bubbles during manufacture appears quite regular.

fractography

pores

gas

manufacture


Input: Thus, these pores are modeled as circles in FE models.

pores

as

FE


Input: The size of these pores and their distance to a free surface of the tested specimens are extracted from Scanning Electron Microscope images.

pores

free surface

extracted

images

Scanning Electron Microscope


Input: Moreover, it has been mentioned in the literature that statistical parameters of surface roughness can not fully describe the detrimental effect of this type of defect to the fatigue life of the associated component.

parameters

defect

surface roughness

fatigue life

component


Input: Thus, in our FE model, the surface topography, which was measured using stylus-based profilometer, is explicitly modeled.

FE

surface topography

profilometer


Input: The finite element results are then post-processed by our in-house software to extract the Smith–Watson–Topper (SWT) fatigue indicator parameter (FIP).

finite element

software

parameter

fatigue


Input: The SWT parameter is calculated at each element centroid of the FE mesh, i.e., the local indicator.

parameter

element

FE


Input: Afterward, an average value of the SWT parameter over a so-called critical area whose center is located at the considered centroid is also calculated, i.e., the average indicator.

average

parameter

average

area


Input: The results show that the local SWT indicator is too conservative in predicting the fatigue life of the AM Ti64 alloys while the average SWT one can provide good results.

fatigue life

AM

alloys

average


Input: A complete metallurgical and mechanical assessment of additively-manufactured maraging tool steels has been undertaken, beginning with the initial powder and ending at hybrid builds.

metallurgical

mechanical

maraging

steels

powder

builds


Input: The effect of powder recycling on powder characteristics is investigated using flowability, size distribution, and density measurements.

powder

powder

distribution

density measurements


Input: Virgin and re-used powder have similar characteristics in terms of size distribution and chemical and phase homogeneity, but no flowability.

powder

distribution

phase


Input: A microstructural characterization of the as-built and heat-treated samples is undertaken, showing the phase evolution, and the formation of porosity between build layers.

microstructural characterization

heat-treated

phase evolution

porosity

build layers


Input: The age-hardening response of the alloy at 490 °C and 650 °C is demonstrated to be similar to the material in the wrought condition.

alloy

be

material

wrought


Input: Finally, hybrid build scenarios are examined–maraging steel powder deposited onto C300 maraging steel, as well as H13 tool steel substrates–using digital image correlation.

build

maraging steel

maraging steel

as

as

steel

tool

digital image correlation


Input: In both cases, the interface remains coherent without any sign of de-bonding during tensile deformation.

interface

deformation

tensile


Input: In the case of the maraging steel powder/C300 substrate, the deformation is homogeneous throughout until failure localizes away from the interface.

maraging steel

substrate

deformation

homogeneous

failure

interface


Input: In the case of the maraging steel powder/H13 substrate, the deformation is predominantly within the substrate until failure localizes at the interface.

maraging steel

substrate

deformation

failure

interface


Input: A heat treatment strategy for the maraging steel powder/H13 tool steel substrate is proposed.

heat treatment

maraging steel

H13 tool steel


Input: The effect of electrode positive time cycle (% EP) of the alternating current TIG process has been investigated for aluminium wire + arc additive manufacture of linear walls.

electrode

TIG process

additive manufacture

aluminium

arc


Input: The study considered the effect on oxide removal, linear wall dimensions, microstructure, mechanical properties as well as the effect on electrode wear.

oxide

as

as

dimensions

microstructure

mechanical properties

electrode


Input: Microstructure analysis showed a noticeable increase in the grain size for higher% EP.

Microstructure

grain size


Input: The study also showed that% EP had no significant effect on mechanical properties.

mechanical properties


Input: The study also indicated that there could be other contributing factors to wall dimensions.

be

dimensions


Input: For aluminium wire + arc additive manufacture of linear walls, minimum cleaning ranged between 10% EP and 20% EP.

aluminium

arc

additive manufacture

cleaning


Input: Reverted austenite is a metastable phase that can be used in maraging steels to increase ductility via transformation-induced plasticity or TRIP effect.

austenite

be

maraging steels

metastable

ductility

plasticity


Input: In the present study, 18Ni maraging steel samples were built by selective laser melting, homogenized at 820 °C and then subjected to different isothermal tempering cycles aiming for martensite-to-austenite reversion.

maraging steel

selective laser melting

homogenized

isothermal


Input: Thermodynamic simulations were used to estimate the inter-critical austenite + ferrite field and to interpret the results obtained after tempering.

simulations

austenite

ferrite

tempering


Input: In-situ synchrotron X-ray diffraction was performed during the heating, soaking and cooling of the samples to characterize the martensite-to-austenite reversion kinetics and the reverted austenite stability upon cooling to room temperature.

In-situ

samples

X-ray diffraction

heating

cooling

cooling

austenite

temperature


Input: The reverted austenite size and distribution were measured by Electron Backscattered Diffraction.

austenite

distribution

Diffraction


Input: Results showed that the selected soaking temperatures of 610 °C and 650 °C promoted significant and gradual martensite-to-austenite reversion with high thermal stability.

temperatures

thermal stability


Input: Tempering at 690 °C caused massive and complete austenitization, resulting in low austenite stability upon cooling due to compositional homogenization.

Tempering

cooling

homogenization

austenite


Input: The process of additive manufacturing (AM) has rapidly developed over the past two decades and is now addressing the needs of industry for fast production of samples with tailored properties and complex geometries.

process

samples

properties

complex geometries

additive manufacturing

AM

production

industry


Input: One of the most common alloys fabricated from powder using the Laser Powder Bed Fusion (L-PBF) method is AlSi10Mg.

alloys

powder

Laser Powder Bed Fusion

L-PBF


Input: The effects of the inherent anisotropy and existing porosity in AM AlSi10Mg were investigated in terms of thermophysical properties, namely thermal conductivity, diffusivity, heat capacity and thermal expansion.

anisotropy

porosity

thermal conductivity

AM

properties

heat capacity

thermal expansion

diffusivity


Input: In both cases, the sample showed abnormal thermal expansion and conductivity, as compared to a conventionally fabricated sample.

sample

thermal expansion

fabricated

conductivity

as


Input: After heat treatment, macro- and microstructure analysis confirmed that thermally induced porosity (TIP) had occurred.

heat treatment

microstructure

porosity


Input: The anisotropic behaviors of thermal conductivity, diffusivity and thermal expansion were found to be related to the texture, preferred orientation and pore distribution of the aluminum grains in the L-PBF-treated samples.

anisotropic

thermal conductivity

pore

diffusivity

thermal expansion

orientation

distribution

samples

be

aluminum

texture


Input: Design for additive manufacturing (DFAM) guidelines are important for helping designers avoid iterations and leverage the design freedoms afforded by additive manufacturing (AM).

Design for additive manufacturing

design freedoms

additive manufacturing

AM


Input: This paper describes how quantitative design guidelines are compiled for a polymer selective laser sintering (SLS) process via a metrology study.

quantitative

process

metrology

design

polymer

laser sintering

SLS


Input: As part of the metrology study, a test part is designed to focus specifically on geometric resolution and accuracy of the polymer SLS process.

As

polymer

metrology

process

designed

resolution

accuracy


Input: The test part is compact, allowing it to be easily inserted into existing SLS builds and therefore eliminating the need for dedicated metrology builds.

compact

SLS

be

builds

builds

metrology