Input: Quality control (three-point bending tests and light microscopy) was routinely conducted on standard specimens printed on the same tray with the components.

Quality control

standard

three-point bending tests

microscopy

components


Input: The learning process included two iteration steps that were executed to improve and optimize the structural design.

process

structural design


Input: The final 3D printed objects, the students’ presentations, their experience, as reflected in their final reports, and their personal written evaluations, lead to the conclusion that the projects served as useful learning experience for engineering education.

3D printed

as

lead

as

engineering


Input: Here we report a pre-fractal antenna design based on the Sierpinski tetrahedron that has been developed with additive manufacturing.

design

additive manufacturing


Input: The Sierpinski tetrahedron-based antenna was simulated with finite element method (FEM) modeling and experimentally tested to highlight its potential for wideband communications.

finite element method

FEM

modeling


Input: The Sierpinski tetrahedron-based antennas were fabricated by two methods, the first involves printing the antenna out of acrylonitrile butadiene styrene (ABS), followed by spin casting a coating of an ABS solution containing graphene flakes produced through electrochemical exfoliation, the second method involves 3D printing the antenna from graphene-impregnated polylactic acid (PLA) filament directly without any coating.

fabricated

flakes

electrochemical

acrylonitrile butadiene styrene

ABS

ABS

graphene

polylactic acid

PLA

filament

casting

3D printing

coating

coating


Input: These antennas incorporate the advantages of 3D printing which allows for rapid prototyping and the development of devices with complex geometries.

3D printing

rapid prototyping

complex geometries


Input: Due to these manufacturing advantages, self-similar antennas like the Sierpinski tetrahedron can be realized which provide increased gain and multi-band performance.

manufacturing

be

gain

performance


Input: Lattice structures fabricated via Additive Manufacturing (AM) offer improved performance over traditional manufacturing methods, however, predicting their mechanical behaviour both accurately and with acceptable computational efficiency remains a challenge.

Lattice structures

fabricated

performance

mechanical behaviour

computational efficiency

Additive Manufacturing

AM

traditional manufacturing

accurately


Input: AM associated defects combined with multiple high aspect-ratio strut elements require fine 3D finite-element (FE) meshes; resulting in high computational complexity that limits the number of lattice unit cells that can be practically simulated.

AM

defects

complexity

limits

strut

elements

FE

be

lattice unit

cells


Input: Alternatively, Euler-Bernoulli or Timoshenko beam elements can be specified to reduce computational complexity.

beam

be

complexity


Input: However, these beam elements are typically based on idealised representations that exclude AM associated defects.

beam

AM

defects


Input: This research proposes a novel method which combines data driven AM defect modelling, Markov Chains and Monte Carlo (MCS) simulation techniques to predict the stiffness of an AM lattice structure.

research

data

structure

AM

AM

modelling

simulation

stiffness


Input: Furthermore, this method accommodates stochastic distributions of AM associated defects within computationally effective beam models; thereby enabling the simulation of large-scale lattice structures at a relatively low computational cost.

stochastic distributions

defects

AM

beam

simulation

lattice structures


Input: The proposed method is aimed at reliability analysis or a probabilistic approach to structural analysis of AM lattice structures.

reliability

structural analysis

AM


Input: The combination of generating AM strut digital realisations and MCS, resulted in a variety of possible strut deformation shapes and effective diameters under axial compression.

AM

strut

deformation

compression


Input: The propagation of effective diameter variability to the lattice-scale level displayed the possible variation in the mechanical response of AM lattice structure.

diameter

variation

mechanical response

structure

AM


Input: Simulations are validated and insight into how a lattice structures unit cell topology affects simulation accuracy is discussed.

Simulations

lattice structures

cell topology

simulation accuracy


Input: The use of laser additive manufacturing based on melting of injected zirconium powder under localized shielding was evaluated in terms of microstructures and mechanical properties of thin wall structures.

laser additive manufacturing

melting

zirconium powder

microstructures

mechanical properties


Input: The material was characterized in both the laser travel and the build directions.

material

laser

build directions


Input: The microstructures, tensile properties and fracture behavior were assessed for deposits made using as-received and recycled powder.

microstructures

powder

tensile properties

fracture

recycled


Input: Electron backscattered diffraction and transmission electron microcopy revealed a fine structure of Zr-α laths with nano-scale iron-rich precipitates at the lath interfaces.

diffraction

transmission

structure

nano-scale

precipitates


Input: The properties of the fabricated components, which were made using new as-received powder were comparable to a Zr-2.5Nb alloy substrate, with yield strengths of over 569 MPa and uniform strains up to the ultimate tensile stress ranging from 8.5 to 9.9%.

properties

fabricated

MPa

components

powder

alloy

yield strengths

tensile stress


Input: However, when recycled powder was used, the ductility dropped with total strains to failure of 1.0–7.5%, as a result of porosity and unmelted powder particles serving as brittle inclusions in the deposited material.

recycled

failure

powder

as

powder particles

as

inclusions

material

ductility

porosity


Input: 3D printed AlSi10Mg can be used in electrical applications once heat treated Electrical resistivity values once heat treated are comparable to cast alloy values Resistivity of as-built AlSi10Mg increases by 27% depending on build orientation Heat treatment can reduce as-built resistivity by 33% Additive manufacturing (AM) opens up a design freedom beyond the limits of traditional manufacturing techniques.

3D printed

cast

Additive manufacturing

AM

traditional manufacturing

be

alloy

electrical applications

heat

heat

design freedom

limits

Electrical resistivity

Resistivity

resistivity

build orientation


Input: Electrical windings created through AM could lead to more powerful and compact electric motors, but only if the electrical properties of the AM printed part can be shown to be similar to conventionally manufactured systems.

Electrical

AM

compact

AM

lead

be

be

electrical properties

manufactured


Input: Until now, no study has reported on the suitability of AM parts for electrical applications as there are few appropriate materials available to AM for this purpose.

AM parts

electrical applications

as

materials

AM


Input: AlSi10Mg is a relatively good electrical conductor that does not have the same reported issues associated with processing pure aluminium or copper via selective laser melting (SLM).

conductor

aluminium

copper

electrical

selective laser melting

SLM


Input: Here, experiments were conducted to test the effects of geometry and heat treatments on the resistivity of AlSi10Mg processed by SLM.

geometry

heat treatments

SLM

resistivity


Input: It was found that post heat treatments resulted in a resistivity that was 33% lower than the as-built material.

heat treatments

resistivity

material


Input: The heat treatment also eliminated variance in the resistivity of as-built parts due to initial build orientation.

heat treatment

resistivity

build orientation


Input: By conducting these tests, it was found that, with this material, there is no penalty in terms of higher resistivity for using AM in electrical applications, thus allowing more design freedom in future electrical applications.

material

resistivity

AM

electrical applications

electrical applications

design freedom


Input: Future exploration missions beyond low-Earth orbit would significantly benefit from a closed loop recyclable Additive Manufactured capability, allowing the production of general purpose tools and items in a time and cost effective manner.

recyclable

Additive Manufactured

production

tools


Input: To realize this ambition, we present a feasibility study of a Solvent-Cast Direct-Write method using Polyvinyl Alcohol as biodegradable material.

feasibility

as

material


Input: Process parameters such as solution viscosity, evaporation rate, print pressure and scan speed are optimized in order to achieve a consistent and reliable print outcome.

Process parameters

pressure

as

viscosity

evaporation rate

print

print

scan speed


Input: We demonstrate the process by fabricating test complex geometries of sample specimens.

process

complex geometries

sample

fabricating


Input: Moreover, we report on the mechanical properties of printed geometries as well as the recyclability aspects.

mechanical properties

geometries

recyclability

as

as


Input: The aerospace, automotive and medical industries are suffering from significant number of counterfeited metallic products that not only have caused financial losses but also endanger lives.

aerospace

automotive

medical industries

metallic


Input: The rapid development of additive manufacturing technologies makes such a situation even worse.

additive manufacturing


Input: In this investigation, we successfully applied a novel hybrid powder delivery selective laser melting (SLM) approach to embed dissimilar tagging material (Cu10Sn copper alloy) safety features (e.g.

powder

material

copper alloy

selective laser melting

SLM

safety


Input: QR code) into metallic components made of 316 L stainless steel.

metallic

stainless steel

components


Input: X-ray imaging was found to be a suitable method for the identification of the embedded safety features up to 15 mm in depth.

X-ray imaging

be

safety

mm


Input: X-ray fluorescence was used for the chemical composition identification of the imbedded security tagging material.

X-ray

fluorescence

chemical composition

material


Input: A criterion for the selection of tagging material, its dimensions and imbedding depth is proposed.

material

dimensions


Input: The multiple material SLM technology was shown to offer the potential to be integrated into metallic component production for embedding anti-counterfeiting features.

material

be

metallic

technology

component


Input: The development of cooling devices is important for many industrial products, and the lattice structure fabricated by additive manufacturing is expected to be useful for effective liquid cooling.

cooling

additive manufacturing

cooling

industrial

lattice structure

fabricated

be


Input: However, lattice density should be carefully designed for an effective arrangement of coolant flow.

lattice density

designed

be

coolant


Input: In this research, we optimize the lattice density distribution using a lattice structure approximation and the gradient method.

research

distribution

lattice density

lattice structure


Input: Fluid flow is approximated by deriving effective properties from the Darcy–Forchheimer law and analyzing the flow according to the Brinkman–Forchheimer equation.

Fluid flow

properties


Input: We use a simple basic lattice shape composed of pillars, optimizing only its density distribution by setting the pillar diameter as the design variable.

simple

lattice

diameter

density distribution

as

design


Input: Steady-state pressure and temperature reductions are treated as multi-objective functions.

pressure

temperature

as


Input: Through 2D and 3D numerical studies, we discuss the validity and limitations of the proposed method.


Input: Although observable errors in accuracy exist between the results obtained from the optimization and full scale models, relative performance optimization was considered successful.

errors

optimization

performance optimization

accuracy


Input: Additive manufacturing has seen large growth due to its numerous process advantages, yet some undesirable defects in additive manufactured (AM) products include pores and micro-cracks.

Additive manufacturing

additive manufactured

AM

process

defects

micro-cracks

pores


Input: These defects weaken the high temperature oxidation resistance of the final parts.

defects

temperature

oxidation resistance


Input: In this work, laser shock peening (LSP) is used as a post-treatment method to change the surface characteristics of selective laser melted (SLM) nano-TiC particle-reinforced Inconel 625 nanocomposites (TiC/IN625).

laser

peening

post-treatment

selective laser melted

SLM

as

Inconel 625

surface


Input: The effects of LSP on surface morphology, residual stress, microhardness, microstructure, and high temperature oxidation behavior of fabricated parts are studied.

surface morphology

residual stress

microhardness

microstructure

fabricated

temperature

oxidation


Input: The results indicate pores in the as-built sample can be closed by the severe plastic deformation, which is induced by LSP.

pores

plastic deformation

sample

be


Input: The maximum hardness is found to reach 462 ± 7 HV with a ∼ 460 μm hardened layer, and the surface stress state transforms from tensile to compressive after LSP.

hardness

stress

tensile

hardened

surface


Input: The full width at half maximum (FWHM) values of the (111) and (200) diffraction broaden, which can be attributed to grain refinement and an increase in lattice strain in the LSP samples.

diffraction

grain refinement

be

lattice

samples


Input: Dislocation walls and dislocation tangles with high dislocation density form in the LSP sample.

Dislocation

dislocation

sample

dislocation density


Input: Compared with as-built sample, the LSP samples exhibit lower mass gain after oxidation at 900 °C for 100 h, indicating that LSP samples have greater oxidation resistance at high temperature.

sample

samples

samples

gain

temperature

oxidation

oxidation resistance


Input: The underlying mechanism governing the high temperature oxidation resistance is proposed based on the experimental results.

mechanism

experimental

temperature

oxidation resistance


Input: This study shows that LSP can be used as an effective method to modify the surface characteristics of SLM TiC/IN625.

be

as

surface

SLM


Input: Many applications require structures composed of layers of heterogeneous materials and prefabricated components embedded between the layers.

heterogeneous

components


Input: The existing additive manufacturing process based on layered object manufacturing is not able to handle multiple layer materials and can not embed prefabricated components.

additive manufacturing process

manufacturing

layer

components


Input: Moreover, the existing process imposes restrictions on the material options.

process

material


Input: This significantly limits the type of heterogeneous structures that can be manufactured using traditional additive manufacturing.

limits

heterogeneous

be

additive manufacturing


Input: This paper presents an extension of sheet lamination object manufacturing process by using a robotic cell to perform the sheet manipulation and handling.

sheet lamination

manufacturing process

cell

sheet


Input: It makes the following three advances: (1) enabling the use of multi-material layers and inclusion of prefabricated components between the layers, (2) developing an algorithmic foundation to facilitate automated generation of robot instructions, and (3) identifying the relevant process constraints related to speed, accuracy, and strength.

multi-material

process

inclusion

components

robot

accuracy

strength


Input: We demonstrate the system capabilities by using three case studies.

case studies


Input: Pure Zn bulk samples of good formation quality and high tensile properties were produced.

Zn

samples

quality

tensile properties


Input: The effect of scanning speed on grain size, morphology and texture was clarified.

scanning speed

grain size

morphology

texture


Input: Crystallographic effects resulted to strong anisotropy in mechanical properties.

anisotropy

mechanical properties


Input: The existence of tiny pores in LPBF samples influenced corrosion behavior.

pores

corrosion behavior

LPBF


Input: Corrosion rate increased with increasing scanning speed at the initial stage of immersion, and the gap narrowed as immersion time passed.

Corrosion

scanning speed

as


Input: Laser powder bed fusion (LPBF) has been previously used to produce customized medical implants from biodegradable Zn and its alloys.

Laser powder bed fusion

LPBF

medical implants

Zn

alloys


Input: In this study, we investigated the effect of the grain structure on the mechanical properties and in vitro corrosion behavior of pure Zn samples, by varying the scanning speed and building direction during the LPBF process.

grain structure

mechanical properties

samples

corrosion behavior

Zn

scanning speed

building direction

LPBF


Input: Increasing the scanning speed from 300 to 700 mm/s resulted in finer grains, irregular grain morphology, and a weaker grain texture, which enhanced the strength and ductility.

scanning speed

grains

grain

grain

strength

ductility


Input: Vertically built LPBF Zn tensile samples had higher strength and ductility compared with horizontally built samples, indicating strong anisotropy of the mechanical properties.

LPBF

tensile

strength

ductility

anisotropy

samples

samples

mechanical properties


Input: Electrochemical tests revealed that the in vitro corrosion behavior was not strongly correlated with the scanning speed.

Electrochemical tests

corrosion behavior

correlated

scanning speed


Input: This was attributable to the random distribution of tiny pores on the surface of the LPBF samples, although immersion tests showed that the sample prepared with the highest scanning speed exhibited the highest corrosion rate.

distribution

surface

sample

corrosion

pores

LPBF

scanning speed


Input: With increasing immersion time in Hank’ s solution, the Zn2+ concentrations of the samples produced with different scanning speeds increased, their pH stabilized, and the differences between the corrosion rates narrowed.

s

samples

pH

corrosion

scanning speeds


Input: The effects of the processing parameters on the final performance of the samples could be well explained by the grain structures.

parameters

performance

samples

grain structures

be


Input: The findings of this study afford bases for selecting the processing parameters for optimizing the properties of LPBF-produced Zn parts for biodegradable applications.

parameters

properties

Zn


Input: Existing powder feedstock metrics for powder bed fusion (PBF) additive manufacturing (AM) are related to packing efficiency and flowability, and newer techniques, such as powder rheometry and dynamic avalanche testing, have received recent attention in the literature.

powder feedstock

powder bed fusion

PBF

additive manufacturing

AM

as

dynamic

testing


Input: To date, however, no powder characterization technique is able to predict the spreadability of AM feedstock.

powder

AM


Input: This study endeavored to establish viable powder spreadability metrics through the development of a spreadability testing rig that emulates the recoating conditions present in commercial PBF AM systems.

powder

testing

PBF AM


Input: As no metrics for spreadability currently exist, four potential metrics were evaluated in a 3∙23 split plot experimental design.

As

experimental design


Input: These four metrics were: (1) the percentage of the build plate covered by spread powder, (2) the rate of powder deposition, (3) the average avalanching angle of the powder, and (4) the rate of change of the avalanching angle.

build plate

spread

deposition

average

powder

powder

powder


Input: Three samples of gas atomized, Al-10Si-0.5 Mg PBF powder representing differing degrees of quality were used as the levels of the powder quality input variable.

samples

quality

gas atomized

Mg

powder

as

powder


Input: As no powder quality metrics have been shown to be indicative of powder spreadability in PBF, various bulk powder characteristics were used as the powder quality indicator during ANOVA.

As

powder

be

powder

powder

as

powder

PBF


Input: Of the four metrics tested, the average avalanching angle, while statistically dependent of the powders angle of repose, showed poor correlation with experimental data.

average

experimental data

powders


Input: poor build plate coverage and powder clumping, as measured by the viable spreading metrics.

build plate

powder

as


Input: Other processing parameters, such as the recoating speed and the recoater blade material were shown to also influence the spread quality.

parameters

spread quality

as

material

recoater blade


Input: A design strategy for lattice cell configurations beyond Maxwell criterion.

design

lattice

Maxwell criterion

cell


Input: Established theoretical models to predict compressive modulus and strength.

theoretical models

strength


Input: Compressive tests and μ-CT to assess mechanical properties and defects.

Compressive tests

mechanical properties

defects


Input: A finite element modeling method based on inherent manufacturing defects.

finite element

defects

manufacturing


Input: A comparison of experimental and theoretical results rendered minimal deviation.

experimental

theoretical


Input: The development of additive manufacturing (AM) technology exhibits potential for the design and manufacturing of complex lattice structures.

additive manufacturing

AM

manufacturing

technology

design

lattice structures


Input: Herein, a novel design strategy is proposed for the lattice unit cell configurations, including triangular prism (T), quadrangular prism (Q) and hexagonal prism (H), by considering the tight spatial arrangement and manufacturing constraints.

design

lattice unit

hexagonal

cell

manufacturing constraints


Input: Moreover, the influence of altering the degree of freedom of nodes, caused by additional struts, on mechanical performance and energy absorption capacity is systematically investigated by theoretical modeling, experimental characterization and finite element method.

struts

mechanical

energy absorption capacity

theoretical

experimental

finite element method

modeling


Input: A series of lattice core sandwich panels is designed and manufactured by selective laser melting (SLM).

lattice core

designed

manufactured

selective laser melting

SLM


Input: X-ray micro-computed tomography (μ-CT) is carried out to obtain the realistic geometrical information.

X-ray micro-computed tomography


Input: Quasi-static uniaxial compressive tests are performed to investigate the failure mechanism and mechanical performance.

Quasi-static

compressive tests

failure mechanism

mechanical


Input: The results reveal that the joint connectivity of the unit cell increased with the increase of the number of the struts, resulting in superior compressive modulus and ultimate strength.

joint

unit cell

struts

ultimate strength


Input: The main deformation mode of cells is gradually changed from bending-dominated to stretch-dominated with the increase of the joint connectivity.

deformation

joint

cells


Input: The proposed design ensures the performance consistency of the manufactured struts and facilitates the theoretical predictions and analysis.

design

performance consistency

manufactured

theoretical predictions


Input: Furthermore, the specific energy absorption of the structure also increased with the increase of joint connectivity.

specific energy absorption

structure

joint


Input: In the case of unit cells with different configurations, T series rendered superior specific strength and specific energy absorption, whereas Q series exhibited excellent specific stiffness.

unit cells

specific energy absorption

specific strength

specific stiffness


Input: Additive manufacturing (AM) is rapidly moving from research to commercial applications due to its ability to produce geometric features difficult or impossible to generate by conventional machining.

Additive manufacturing

AM

conventional machining

research


Input: Fielded components need to endure fatigue loadings over long operational lifetimes.

components

fatigue


Input: This work evaluates the ability of shot and laser peening to enhance the fatigue lifetime and strength of AM parts.

laser peening

fatigue

strength

AM parts


Input: As previously shown, peening processes induce beneficial microstructure and residual stress enhancement; this work takes a step to demonstrate the fatigue enhancement of peening including for the case of geometric stress risers as expected for fielded AM components.

As

as

peening

peening

AM

microstructure

step

residual stress

fatigue

stress

risers


Input: We present AM sample fatigue results with and without a stress riser using untreated baseline samples and shot and laser peening surface treatments.

AM

laser peening

fatigue

stress

riser

samples


Input: Laser peening is clearly shown to provide superior fatigue life and strength.

Laser peening

fatigue life

strength


Input: We also investigated the ability of analysis to select laser peening parameters and coverage that can shape and/or correctively reshape AM components to a high degree of precision.

laser peening

AM

precision


Input: We demonstrated this potential by shaping and shape correction using our finite element based predictive modeling and highly controlled laser peening.

shaping

laser peening

finite element

modeling


Input: The present work addressed the challenges of identifying applicable Non-Destructive Testing (NDT) techniques suitable for inspection and materials characterization techniques for Wire and Arc Additive Manufacturing (WAAM) parts.

Non-Destructive Testing

inspection

NDT

materials

Wire and Arc Additive Manufacturing

WAAM


Input: With the view of transferring WAAM to the industry and qualifying the manufacturing process for applications such as structural components, the quality of the produced parts needs to be assured.

WAAM

manufacturing process

industry

as

be

components

quality


Input: Thus, the main objective of this paper is to review the main NDT techniques and assess the capability of detecting WAAM defects, for inspection either in a monitoring, in-process or post-process scenario.

NDT

defects

post-process

WAAM

inspection


Input: Radiography and ultrasonic testing were experimentally tested on reference specimens in order to compare the techniques capabilities.

Radiography

testing


Input: Metallographic, hardness and electrical conductivity analysis were also applied to the same specimens for material characterization.

hardness

electrical conductivity

material


Input: Experimental outcomes prove that typical WAAM defects can be detected by the referred techniques.

Experimental

defects

WAAM

be


Input: The electrical conductivity measurement may complement or substitute some destructive methods used in AM processing.

electrical conductivity

AM


Input: Compressive creep properties of AlSi10Mg parts produced by additive manufacturing selective laser melting (AM-SLM) were studied using a spark plasma sintering (SPS) apparatus, capable of performing uniaxial compressive creep tests.

creep

additive manufacturing

spark plasma sintering

SPS

laser

creep tests


Input: Stress relief-treated specimens were tested under an applied stress of 100–130 MPa in the 175–225 °C temperature range.

Stress

stress

MPa

temperature range


Input: The creep parameters (i.e., stress exponent n and apparent activation energy Q), were empirically determined.

creep

stress

n


Input: The experimental results, together with microstructural examination of specimens, indicate that plastic deformation was controlled by dislocation activity.

experimental

microstructural

dislocation

plastic deformation


Input: Furthermore, it is suggested that the annihilation process of dislocations during creep was enhanced by the electric current.

process

dislocations

creep


Input: This experimental study investigates the combined effect of the three primary Additive Manufacturing (AM) build orientations (0°, 45°, and 90°) and an extensive array of heat treatment plans on the plastic anisotropy of maraging steel 300 (MS1) fabricated on the EOSINT M280 Direct Metal Laser Sintering (DMLS) system.

experimental

investigates

fabricated

Additive Manufacturing

AM

heat treatment

Direct Metal Laser Sintering

DMLS

build orientations

plastic

maraging steel

anisotropy


Input: The alloy's microstructure, hardness, tensile properties and plastic strain behaviour have been examined for various strengthening heat-treatment plans to assess the influence of the time and temperature combinations on plastic anisotropy and mechanical properties (e.g.

alloy

plastic

plastic

microstructure

mechanical properties

hardness

tensile properties

anisotropy

strengthening

temperature


Input: strength, ductility).

strength

ductility


Input: A comprehensive visual representation of the material's overall mechanical properties, for all three AM build orientations, against the various heat treatment plans is offered through time–temperature contour maps.

material

mechanical properties

orientations

AM

heat treatment

temperature

contour


Input: Considerable plastic anisotropy has been confirmed in the as-built condition, which can be reduced by aging heat-treatment, as verified in this study.

plastic

be

as

anisotropy


Input: However, it has identified that a degree of transverse strain anisotropy is likely to remain due to the AM alloy's fabrication history, a finding that has not been previously reported in the literature.

strain anisotropy

AM

fabrication

alloy


Input: Moreover, the heat treatment plan (6h at 490 °C) recommended by the DMLS system manufacturer has been found not to be the optimal in terms of achieving high strength, hardness, ductility and low anisotropy for the MS1 material.

heat treatment

DMLS

manufacturer

be

material

strength

hardness

ductility

anisotropy


Input: With the use of the comprehensive experimental data collected and analysed in this study, and presented in the constructed contour maps, the alloy's heat treatment parameters (time, temperature) can be tailored to meet the desired strength/ductility/anisotropy design requirements, either for research or part production purposes.

experimental data

research

contour

design

alloy

be

heat treatment

production

temperature


Input: We have investigated the relationship between structure and thermal conductivity in additively manufactured interpenetrating A356/316L composites.

structure

thermal conductivity

additively manufactured

composites


Input: We used X-ray microcomputed tomography to characterize the pore structure in as-fabricated composites, finding microporosity in both constituents as well as a 50 μm thick layer of interfacial porosity separating the constituents.

X-ray

pore

microporosity

porosity

composites

as

as

layer


Input: We measured the thermal conductivity of a 43 vol% 316L composite to be 53 Wm−1K−1, which is significantly less than that predicted by a simple rule-of-mixtures approximation, presumably because of the residual porosity.

thermal conductivity

porosity

composite

be

predicted

residual

simple


Input: Motivated by these experimental results we used periodic homogenization theory to determine the combined effects of porosity and unit cell structure on the effective thermal conductivity.

experimental

unit cell

structure

homogenization

porosity

effective thermal conductivity


Input: This analysis showed that in fully dense composites, the topology of the constituents has a weak effect on the thermal conductivity, whereas in composites with interfacial porosity, the size and structure of the unit cell strongly influence the thermal conductivity.

fully dense

composites

composites

topology

structure

unit cell

thermal conductivity

porosity

thermal conductivity


Input: We also found that an approximation formula of the strong contrast expansion method gives excellent estimates of the effective thermal conductivity of these composites, providing a powerful tool for designing functionally graded composites and for identifying mesostructures with optimal thermal conductivity values.

effective thermal conductivity

composites

composites

tool

functionally graded

thermal conductivity


Input: In this work, the performance of a focus variation instrument for measurement of areal topography of metal additive surfaces was investigated.

performance

variation

measurement

topography

metal

additive


Input: Samples were produced using both laser and electron beam powder bed fusion processes with some of the most common additive materials: Al-Si-10Mg, Inconel 718 and Ti-6Al-4V.

Samples

electron beam

laser

bed fusion

additive

Inconel 718


Input: Surfaces parallel and orthogonal to the build direction were investigated.

Surfaces

build direction


Input: Measurement performance was qualified by visually inspecting the topographic models obtained from measurement and quantified by computing the number of non-measured data points, by estimating local repeatability error in topography height determination and by computing the value of the areal field texture parameter Sa.

Measurement

measurement

topography

data

repeatability error

parameter

texture


Input: Variations captured through such indicators were investigated as focus variation-specific measurement control parameters were varied.

Variations

parameters

as

measurement


Input: Changes in magnification, illumination type, vertical resolution and lateral resolution were investigated.

magnification

vertical

resolution

resolution


Input: The experimental campaign was created through full factorial design of experiments, and regression models were used to link the selected measurement process control parameters to the measured performance indicators.

experimental

factorial design

regression models

parameters

performance

measurement


Input: The results indicate that focus variation microscopy measurement of metal additive surfaces is robust to changes of the measurement control parameters when the Sa texture parameter is considered, with variations confined to sub-micrometre scales and within 5% of the average parameter value for the same surface and objective.

variation

parameters

parameter

variations

average

surface

microscopy

measurement

measurement

metal

additive

texture


Input: The number of non-measured points and the local repeatability error were more affected by the choice of measurement control parameters.

repeatability error

parameters

measurement


Input: However, such changes could be predicted by the regression models, and proved consistent once material, type of additive process and orientation of the measured surface are set.

be

material

additive

regression models

orientation

surface

set


Input: Hot Isostatic Pressing (HIP) is a technique of applying high pressures through a fluid medium at high temperatures to enclosed powders, castings and pre-sintered metal parts to eliminate porosity.

Hot Isostatic Pressing

HIP

pressures

fluid

powders

metal

temperatures

pre-sintered

porosity


Input: Due to uniform volumetric shrinkage expected from this process, it can be a useful post-processing technique for complex-geometry parts fabricated using Additive Manufacturing (AM) techniques.

shrinkage

process

post-processing

fabricated

be

Additive Manufacturing

AM


Input: In order for the technique to work effectively, parts are typically required to have a minimum density of 92%, where surface porosity is closed.

density

porosity

surface


Input: While HIP has been used in conjunction with powder bed fusion AM processes, its use for parts made using Binder Jetting (BJ) has not been investigated in detail due to the limitations of BJ in fabricating sufficiently high-density parts without infiltration.

HIP

powder bed fusion AM processes

Binder Jetting

BJ

BJ

fabricating

infiltration


Input: In this work, detailed investigations on the effect of HIP on BJ parts printed from three different powder configurations, which led to varying levels of porosity, are performed.

HIP

BJ

powder

led

porosity


Input: The effects of HIP on the density, microstructure, tensile strength, and ductility of the resulting parts is reported.

HIP

density

tensile strength

ductility

microstructure


Input: A maximum density of 97.32% was achieved by HIP of printed and sintered parts created via bimodal powders.

density

HIP

sintered

powders


Input: Both the tensile strength and ductility were found to improve following HIP, which suggests that the reduction in porosity is predominant compared to the detrimental effects of grain coarsening.

tensile strength

ductility

porosity

HIP

reduction

grain


Input: Control of the atomic structure, as measured by the extent of the embrittling B2 chemically ordered phase, is demonstrated in intermetallic alloys through additive manufacturing (AM) and characterized using high fidelity neutron diffraction.

atomic structure

as

intermetallic alloys

phase

additive manufacturing

AM

neutron diffraction


Input: As a layer-by-layer rapid solidification process, AM was employed to suppress the extent of chemically ordered B2 phases in a soft ferromagnetic Fe-Co alloy, as a model material system of interest to electromagnetic applications.

As

alloy

as

layer-by-layer

model material

solidification process

AM


Input: The extent of atomic ordering was found to be insensitive to the spatial location within specimens and suggests that the thermal conditions within only a few AM layers were most influential in controlling the microstructure, in agreement with the predictions from a thermal model for welding.

be

AM

welding

microstructure

predictions

model


Input: Analysis of process parameter effects on ordering found that suppression of B2 phase was the result of an increased average cooling rate during processing.

process parameter

phase

average


Input: AM processing parameters, namely interlayer interval time and build velocity, were used to systematically control the relative fraction of ordered B2 phase in specimens from 0.49 to 0.72.

AM

parameters

fraction

phase

build


Input: Hardness of AM specimens was more than 150% higher than conventionally processed bulk material.

Hardness

AM

processed

material


Input: Implications for tailoring microstructures of intermetallic alloys are discussed.

microstructures

intermetallic alloys


Input: Wire–arc additive manufacturing (WAAM) is an emergent method for the production and repair of high value components.

additive manufacturing

WAAM

production

components


Input: Introduction of plastic strain by inter-pass rolling has been shown to produce grain refinement and improve mechanical properties, however suitable quality control techniques are required to demonstrate the refinement non-destructively.

plastic

rolling

grain refinement

mechanical properties

quality control


Input: Specifically, undeformed and rolled specimens have been analysed by spatially resolved acoustic spectroscopy (SRAS), allowing the efficacy of the rolling process to be observed in velocity maps.

spectroscopy

rolling process

be


Input: The work has three primary outcomes (i) differentiation of texture due to rolling force, (ii) understanding the acoustic wave velocity response in the textured material including the underlying crystallography, (iii) extraction of an additional build metric such as layer height from acoustic maps and further useful material information such as minimum stiffness direction.

texture

rolling

crystallography

force

material

as

material

as

build

stiffness


Input: Variations in acoustic response due to grain refinement and crystallographic orientation have been explored.

Variations

orientation

grain refinement


Input: This allowed prior-β grains to be resolved.

grains

be


Input: A basic algorithm has been proposed for the automated measurement, which could be used for in-line closed loop control.

algorithm

closed loop control

automated measurement

be


Input: Additive Manufacturing (AM) professionals often throw around the notion that complexity is free.

Additive Manufacturing

AM

complexity


Input: Indeed, complexity is much easier and potentially cheaper to achieve through AM than through traditional manufacturing, but it is not free.

complexity

AM

traditional manufacturing


Input: Upon attempting to manufacture complex designs, it is quickly found that certain features, or topologies, are more manufacturable than others, with sacrificial support material required for many complex designs.

manufacture

topologies

manufacturable

designs

designs

support material


Input: This will significantly increase machining costs.

machining


Input: Topology Optimization (TO) is a freeform computational design methodology which is ideal for designing lightweight structures through a combination of modeling and rigorous optimization.

Topology Optimization

design

freeform

optimization

lightweight structures

modeling


Input: While AM can realize many complex topologies, there still remain AM manufacturing limitations (such as overhangs), which require customized TO design algorithms beyond freeform TO.

AM

AM

topologies

algorithms

freeform

as

design


Input: In this work, a projection-based TO methodology is presented to design for 3D self-supporting structures–i.e.

methodology

design


Input: structures that do not require sacrificial support material.

support material


Input: The foundation of the presented methodology is a 2D overhang projection framework.

methodology

framework


Input: In addition to expanding the methodology to three dimensions, the algorithm is drastically improved through (1) adopting a new overhang mapping scheme which allows for exact specification of allowable overhang angle, and (2) implementing an adjoint approach to sensitivity calculations to speed up calculation drastically and to allow for scalability.

methodology

algorithm

dimensions

overhang

specification

overhang angle

sensitivity


Input: Using several examples, it is shown that the presented methodology generates self-supporting structures (given a prescribed printable overhang angle) which are entirely manufacturable without any added sacrificial support material.

methodology

manufacturable

self-supporting

overhang angle

support material


Input: Upon printing a couple topologies with mixed success, further customization of the algorithm is proposed for situations where multiple directional-dependent overhang angles are possible in a single AM system.

topologies

algorithm

overhang angles

AM


Input: An analytical process model for predicting the layer height and wall width from the process parameters was developed for wire + arc additive manufacture of Ti-6Al-4V, which includes inter-pass temperature and material properties.

process model

process parameters

material properties

layer height

temperature

wire + arc additive manufacture


Input: Capillarity theory predicted that cylindrical deposits were produced where the wall width was less than 12 mm (radius < 6 mm) due to the large value of the surface tension.

predicted

cylindrical

mm

mm

surface tension


Input: Power was predicted with an accuracy of ±20% for a wide range of conditions for pulsed TIG and plasma deposition.

Power

range

predicted

plasma deposition

accuracy

TIG


Input: Interesting differences in the power requirements were observed where a surface depression was produced with the plasma process due to differences in melting efficiency and/or convection effects.

power

surface

plasma

melting


Input: Finally, it was estimated the impact of controlling the workpiece temperature on the accuracy of the deposit geometry.

impact

workpiece

geometry

temperature

accuracy


Input: Processing of Si and hydroxyapatite reinforced Ti6Al4Vmatrix compositesusinglaser-based directed energy deposition (DED) from powder blends.

Si

hydroxyapatite

powder blends

directed energy deposition

DED


Input: Si addition helped form in situ reactive phases of titanium silicides and vanadium silicides Composites showed higher hardness, lower coefficient of friction and better wear resistance.

Si

titanium silicides

vanadium

silicides

Composites

in situ

hardness

coefficient of friction

wear resistance


Input: Directed-energy deposition (DED) -based additive manufacturing (AM) was explored for composite development using silicon (Si) and hydroxyapatite (HA) in Ti-6Al-4 V (Ti64) matrix for articulating surfaces of load-bearing implants.

deposition

surfaces

DED

additive manufacturing

AM

composite

silicon

Si

hydroxyapatite

Ti-6Al-4 V

load-bearing

implants


Input: Specifically, laser engineered net shaping (LENSTM)–a commercially available DED-based AM technique–was used to fabricate composites from premixed-feedstock powders.

laser engineered net shaping

AM technique

fabricate

composites

powders


Input: The AM’ d composites proved to not only improve upon Ti64’ s mechanical properties but also produced an in-situ Si-based tribofilm during tribological testing that minimized wear induced damage.

AM

composites

s

mechanical properties

in-situ

tribological

wear

testing

damage


Input: Additionally, it was found that with the introduction of Si, titanium silicides and vanadium silicides were formed; allowing for 114% increased hardness, decreased coefficient of friction (COF) and a reduction of wear rate of 38.1% and 70.8%, respectively, for a 10 wt.% Si presence.

Si

titanium silicides

vanadium

silicides

Si

hardness

coefficient of friction

reduction

wear


Input: The produced composites also displayed a positive shift in open-circuit potential (OCP) during linear wear, along with a reduction in the change of OCP from idle to linear wear conditions.

composites

wear

reduction

wear


Input: Additionally, contact resistance (CR) values increased with a maximum value of 1500 ohms due to the formation of Si-based tribofilm on the wear surface.

contact

CR

wear

surface


Input: Such composite development approach using DED-based AM can open up the possibilities of innovating next-generation implants that are designed and manufactured via multi-material AM.

composite

AM

AM

implants

designed

manufactured

multi-material


Input: We investigate experimentally and numerically the influence of the processing conditions on the cross-section of a strand printed by material extrusion additive manufacturing.

material extrusion additive manufacturing


Input: The parts manufactured by this method generally suffer from a poor surface finish and a low dimensional accuracy, coming from the lack of control over the shape of the printed strands.

manufactured

surface finish

dimensional accuracy


Input: Using optical microscopy, we have measured the cross-sections of the extruded strands, for different layer heights and printing speeds.

optical microscopy

cross-sections

extruded

layer heights

printing speeds


Input: For the first time, we have compared the measurements of strands’ cross-sections to the numerical results of a three-dimensional computational fluid dynamics model of the deposition flow.

cross-sections

three-dimensional

deposition

computational fluid dynamics


Input: The proposed numerical model shows good agreement with the experimental results and is able to capture the changes of the strand morphology observed for the different processing conditions.

model

experimental

morphology


Input: The combination of additive manufacturing principles and electron beam (EB) technology allows complex metal parts, featuring excellent quality material, to be produced, whenever traditional methods are expensive or difficult to apply.

additive manufacturing

electron beam

technology

quality

metal

material

be


Input: Today, the optimization of process parameters, for a given metal powder, is generally attained through an empirical trial and error approach.

optimization

process parameters

empirical

error

metal powder


Input: Process simulation can be used as a tool for decision-making and process optimization, since a virtual analysis can help to facilitate the possibility of exploring “what if” scenarios.

Process simulation

be

as

tool

process optimization


Input: In this work, a new type of modelling has been introduced for energy source and powder material properties and it has been included in a thermal numerical model in order to improve the effectiveness and reliability of Electon Beam Melting (EBM) FE simulation.

modelling

source

powder material

FE

model

effectiveness

reliability

Beam

EBM


Input: Several specific subroutines have been developed to automatically calculate the powder properties as temperature functions, and to consider the position of the beam during scanning as well as the material state changes from powder to liquid in the melting phase and from liquid to solid during cooling.

powder

as

as

as

material

powder

beam

scanning

melting

cooling


Input: A comparison of the numerical results and experimental data taken from literature has shown a good forecasting capability.

experimental data


Input: The average deviations of the simulation from an experimental scan line width have been found to be below about 15%.

average

experimental

simulation

be


Input: ISO 25178-2 surface texture from X-ray CT, interlaboratory comparison, is presented.

ISO 25178-2

texture

X-ray CT


Input: Less than 0.5% Sa areal roughness between metrology CT and focus variation values.

roughness

metrology

variation

CT


Input: Artefact design allows separation of surface determination and scaling errors.

design

surface

errors


Input: The study compared the results obtained for the extraction of areal surface texture data per ISO 25178-2 from five X-ray computed tomography (CT) volume measurements from each of four laboratories.

surface texture

data

volume

laboratories

ISO 25178-2

X-ray computed tomography

CT


Input: Two Ti6Al4V ELI (extra-low interstitial) components were included in each of the CT acquisitions.

components

CT


Input: The first component was an additively manufactured (AM) cube manufactured using an Arcam Q10 electron beam melting (EBM) machine.

component

machine

additively manufactured

AM

electron beam melting

EBM

cube


Input: Surface texture data was extracted from CT scans of this part.

Surface texture

data

extracted

CT


Input: The values of selected parameters per ISO 25178-2 are reported, including Sa, the arithmetic mean height, for which the values from the Nikon MCT 225 metrology CT measurements were all within 0.5% of the mean reference focus variation measurement.

parameters

arithmetic mean

metrology

variation

ISO 25178-2

CT

measurement


Input: CT resolution requirements are discussed.

CT


Input: The second component was a machined dimensional test artefact designed to facilitate independent analysis of CT global voxel scaling errors and surface determination errors.

component

machined

designed

CT

voxel

errors

surface

errors


Input: The results of mathematical global scaling and surface determination correction of the dimensional artefact data is reported.

mathematical

surface

data


Input: The dimensional test artefact errors for the XT H 225 commercial CT for length, outside diameter and inside diameter reduced from -0.27%, -0.83% and -0.54% respectively to less than 0.02% after performing mathematical correction.

errors

diameter

diameter

mathematical

CT


Input: This work will assist the development of surface texture correction protocols, help define surface-from-CT measurement envelope limits and provide valuable information for an expanded Stage 2 interlaboratory comparison, which will include a more diverse range of CT systems and technologies, further expanding the surface-from-CT knowledge base.

surface texture

protocols

limits

technologies

measurement

range

CT


Input: Bimetallic structures belong to a class of multi-material structures, and they potentially offer unique solutions to many engineering problems.

multi-material structures

engineering


Input: In this work, bimetallic structures of Inconel 718 and Ti6Al4V (Ti64) alloys were processed using laser engineered net shaping (LENS™).

Inconel 718

alloys

processed

laser engineered net shaping


Input: During LENS™ processing, three build strategies were attempted: direct deposition, compositional gradation and use of an intermediate bond layer.

build strategies

deposition

layer


Input: Inconel 718 and Ti64 alloys exhibit thermal properties mismatch along with brittle intermetallic phase formation at the interface resulting in delamination.

Inconel 718

Ti64 alloys

thermal properties

phase

interface

delamination

brittle


Input: For a successful build, the use of a compositional bond layer (CBL) was employed, which was a mixture of a third material-Vanadium Carbide-with the parent alloys to form an intermediate layer used in bonding the two immiscible alloys.

build

layer

layer

material

Vanadium Carbide

alloys

alloys

bonding


Input: A crack-free bimetallic structure of Inconel 718 and Ti64 was demonstrated.

structure

Inconel 718


Input: Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction and Vickers hardness were used to characterize these bimetallic structures.

Scanning electron microscopy

SEM

energy dispersive spectroscopy

EDS

X-ray diffraction

Vickers hardness


Input: XRD analysis indicated presence of Cr3C2 phases.

XRD


Input: CBL improved the bonding strength by avoiding formation of brittle intermetallic phases such as TiNi3 and Ti2Ni as well as reducing thermal stresses at the interface.

bonding strength

brittle

thermal stresses

as

as

as

interface


Input: Our results successfully demonstrate the formation of Inconel 718 and Ti64 bimetallic structures using a laser-based commercially available additive manufacturing approach.

Inconel 718

additive manufacturing


Input: Additive manufacturing, also known as 3D printing, is a new technology that obliterates the geometrical limits of the produced workpieces and promises low running costs as compared to traditional manufacturing methods.

Additive manufacturing

3D printing

traditional manufacturing

as

as

technology

geometrical limits


Input: Hence, additive manufacturing technology has high expectations in industry.

additive manufacturing

industry


Input: Unfortunately, the lack of a proper quality monitoring prohibits the penetration of this technology into an extensive practice.

quality

penetration

technology


Input: This work investigates the feasibility of using acoustic emission for quality monitoring and combines a sensitive acoustic emission sensor with machine learning.

investigates

feasibility

acoustic emission

quality

acoustic emission

machine


Input: The acoustic signals were recorded using a fiber Bragg grating sensor during the powder bed additive manufacturing process in a commercially available selective laser melting machine.

fiber

sensor

machine

powder bed additive manufacturing

selective laser melting


Input: The process parameters were intentionally tuned to invoke different processing regimes that lead to the formation of different types and concentrations of pores (1.42 ± 0.85%, 0.3 ± 0.18% and 0.07 ± 0.02%) inside the workpiece.

process parameters

workpiece

lead

pores


Input: The classifier, based on spectral convolutional neural network, was trained to differentiate the acoustic features of dissimilar quality.

neural network

quality


Input: In view of the narrow range of porosity, the results can be considered as promising and they showed the feasibility of the quality monitoring using acoustic emission with the sub-layer spatial resolution.

range

resolution

porosity

be

as

feasibility

quality

acoustic emission


Input: An automated python script to slice a macro-scale part into micro-scale layers and assign boundary conditions steps for each layer is presented.

slice

micro-scale

boundary conditions

layer


Input: Key parameter interdependencies of resolution, energy and time are investigated in a series of layer-scaling thermomechanical process models.

parameter

thermomechanical process

resolution


Input: Guidelines for simulation the thermal and stress results of higher resolution by lower resolution for the LPBF modelling are proposed.

simulation

stress

higher resolution

resolution

LPBF


Input: A novel efficient method for simulating powder-solid heat conduction by interface surface convection is presented.

heat conduction

interface


Input: The Laser Beam Powder Bed Fusion (PBF-LB) category of Additive Manufacturing (AM) is currently receiving much attention for computational process modelling.

Laser Beam

process

Bed Fusion

Additive Manufacturing

AM

modelling


Input: Major challenges exist in how to reconcile resolution, energy and time in a real build, with the practical limitations of resolution (layer height and mesh resolution), energy (heat format and magnitude) and time (heating and cooling step times) in the computational space.

resolution

build

resolution

layer height

resolution

magnitude

heat

heating

cooling


Input: A novel thermomechanical PBF-LB process model including an efficient powder-interface heat loss mechanism was developed.

thermomechanical

process model

heat

mechanism


Input: The effect of variations in layer height (layer scaling), energy and time on the temperature and stress evolution was investigated.

variations

evolution

layer height

layer

temperature

stress


Input: The influence of heating step time and cooling step time was characterised and the recommended ratio of element size to layer scaling was presented, based on a macroscale 2D model.

heating

cooling

element size

layer

macroscale 2D


Input: The layer scaling method was effective when scaling up to 4 times the layer thickness and appropriately also scaling the cooling step time.

layer

layer thickness

cooling


Input: This research provides guidelines and a framework for layer scaling for finite element modelling of the PBF-LB process.

research

framework

process

layer

finite element modelling


Input: Additive manufacturing (AM) is a rapidly growing technology that enables the fast production of complex and near-net-shaped (NNS) components.

Additive manufacturing

AM

production

technology

components


Input: Among the many applicable AM methods (particularly powder bed technologies), electron-beam melting (EBM) is gaining increased interest mainly in aerospace and medical industries, due to its inherent advantages for the printing of Ti-6Al-4V alloy.

AM

melting

EBM

powder bed

aerospace

medical industries

Ti-6Al-4V alloy


Input: Although major strides have been made towards understanding the effect of hot isostatic pressure (HIP) on the mechanical properties of Ti-6Al-4V produced by AM, its effect on corrosion performance remains relatively unexplored.

pressure

mechanical properties

corrosion

HIP

AM


Input: To date, the reported corrosion studies remain essentially limited to the selective laser melting (SLM) process, while the corrosion behavior of EBM Ti-6Al-4V and particularly HIPed EBM Ti-6Al-4V have not been fully realized.

corrosion

process

selective laser melting

SLM

EBM

EBM

corrosion behavior


Input: This paper provides a detailed analysis of this corrosion performance, including the stress-corrosion susceptibility of EBM Ti-6Al-4V in as-build condition and after HIP heat treatment.

corrosion

susceptibility

EBM

HIP heat treatment


Input: Microstructure and phase identifications were examined by scanning electron microscopy (SEM) and X-ray diffraction analysis.

Microstructure

phase

scanning electron microscopy

SEM

X-ray diffraction analysis


Input: Corrosion performance was evaluated by electrochemical measurements, including open-circuit potential (OCP), potentiodynamic polarization analysis and impedance spectroscopy (EIS), as well as stress-corrosion examination in terms of slow strain-rate testing (SSRT).

Corrosion

SSRT

electrochemical measurements

potentiodynamic polarization

impedance spectroscopy

EIS

testing

as

as


Input: All of the corrosion tests were carried out in a 3.5 wt.% NaCl solution at ambient temperature.

corrosion

NaCl

temperature


Input: Owing to the natural excellent corrosion resistance of Ti-6Al-4V, the obtained results revealed that the HIP process has only a slight positive effect on the corrosion resistance of Ti-6Al-4V produced by EBM.

corrosion resistance

corrosion resistance

HIP

EBM


Input: This minor improvement may be related to the improved efficiency of the passivation layer that was attributed to the increased β-phase content and the reduction of α/β interfaces.

be

passivation

reduction

layer


Input: In terms of stress corrosion sensitivity, the HIPed specimens exhibited extended time-to-failure (TTF) at the low strain rate at 2.5 10-7 1/sec, where the effect of the corrosive environment was more dominant.

stress

corrosive

corrosion

strain rate


Input: We study linearity assumptions in the transient macroscale mechanical aspect of additive manufacturing (AM) process simulation.

linearity

transient macroscale

mechanical

additive manufacturing

AM

process simulation


Input: Linearity assumptions are often resorted to in combination with calibrated inelastic deformation components to arrive at computationally tractable yet reasonably accurate AM process models.

Linearity

calibrated

deformation

process models

components

accurate


Input: We point out that linearity assumptions permit the independent computation of the response increment in each step of the AM process, and the total mechanical response is the superposition of all the process-step increments.

linearity

computation

step

mechanical response

AM process


Input: In effect, process-step increments are computed with respect to the stress-free reference configuration in each step.

configuration

step


Input: The implication is that the mechanical response increment in each linearised AM process step may be computed in parallel.

mechanical response

AM process

be


Input: geometric or material) is modelled.

material


Input: Distortions in Additive Manufacturing (AM) Laser Metal Deposition (LMD) occur in the newly-built component due to rapid heating and solidification and can lead to shape deviations and cracking.

Additive Manufacturing

AM

Laser Metal Deposition

LMD

heating

component

solidification

cracking

lead


Input: Digital Image Correlation (DIC) is applied together with optical filters to measure in-situ distortions directly on a wall geometry produced with LMD.

Digital Image Correlation

DIC

in-situ

geometry

optical

filters

LMD


Input: The wall shows cyclic expansion and shrinking with the edges bending inward and the top of the sample exhibiting a slight u‐shape as residual distortions.

bending

sample

as


Input: Subsequently, a structural Finite Element Analysis (FEA) of the experiment is established, calibrated against experimental temperature profiles and used to predict the in-situ distortions of the sample.

Finite Element Analysis

experiment

calibrated

experimental

in-situ

sample

profiles


Input: A comparison of the experimental and numerical results reveals a good agreement in length direction of the sample and quantitative deviations in height direction, which are attributed to the material model used.

experimental

sample

quantitative

material


Input: The suitability of the novel experimental approach for measurements on an AM sample is shown and the potential for the validated numerical model as a predictive tool to reduce trial-and-error and improve part quality is evaluated.

experimental

model

trial-and-error

quality

AM

as

tool


Input: In this paper we investigate the use of passive stabilization to support stereolithography (SLA) printing aboard a moving vessel at sea.

passive stabilization

support

stereolithography

SLA

moving vessel


Input: 3D printing is a useful technology onboard a seagoing vessel to support engineering development, shipboard maintenance, and other applications when land-based manufacturing resources are unavailable.

3D printing

technology

engineering development

shipboard maintenance

land-based manufacturing

seagoing

support


Input: SLA printed material is particularly suited for underwater applications requiring sealed housings, since SLA printers are capable of producing high-resolution models that are fully solid and impervious to water.

SLA

sealed housings

SLA printers

material

underwater applications

high-resolution

impervious


Input: Hydrostatic pressure can quickly compromise parts created using standard fused filament fabrication (FFF) 3D printing.

Hydrostatic pressure

standard

fused filament fabrication

FFF

3D printing


Input: However, the dynamic environment onboard a moving vessel could impact the ability of an SLA printer to selectively cure voxels in a liquid resin bath as it undergoes constant motion, and can cause spilling over the walls of the resin tank.

dynamic

impact

cure

liquid resin bath

spilling

resin tank

moving vessel

SLA printer

as


Input: Using passive stabilization platforms onboard moving research vessels, we successfully printed a number of parts with no discernable differences from those produced in a traditional land-based laboratory.

passive stabilization platforms

research vessels

discernable

land-based laboratory


Input: As a practical demonstration of this capability, we printed at sea underwater pressure housings that remained sealed to 200 m water depth with functional integrated internal electronics.

As

underwater pressure housings

integrated internal electronics

water depth


Input: No post-print machining was required to create the sealed housings.

post-print machining

sealed housings


Input: This work lays the foundation for lithographic 3D printing in seagoing oceanographic and naval applications, and additionally presents an economical approach for producing custom waterproof pressure housings in the field.

lithographic 3D printing

seagoing oceanographic

naval applications

waterproof

pressure housings


Input: Direct printing of microstructures using material jetting based additive manufacturing (3D printing) onto PMMA substrates.

microstructures

material jetting

additive manufacturing

3D printing


Input: Substrate surface free energy contributes to both microstructure resolution and adhesion.

Substrate

microstructure

adhesion


Input: Surface modification is an effective mechanism to tailor build–substrate interactions.

Surface modification

mechanism

build

substrate


Input: The ability to directly print 3D microstructures across the surface of large dimension substrates opens up numerous possibilities not feasible with conventional 2D or 2.5D printing or coating techniques.

print

surface

dimension

coating


Input: Demonstrated herein is a method to print 3D microstructures onto clear poly (methyl methacrylate) (PMMA) plates using material jetting technologies.

print

material jetting


Input: Contact angle and profilometry analysis indicated that the VeroCyan™ photopolymer had enhanced wetting of the PMMA surface leading to greater droplet spreading affecting the geometries printed compared to VeroCyan™ integrated models.

Contact

photopolymer

surface

droplet

geometries


Input: The surface chemistry and wetting behaviour played a crucial role in influencing interfacial interactions with the VeroCyan™ photopolymer hence its adhesion to the PMMA surface.

surface

chemistry

surface

photopolymer

adhesion


Input: Additive manufacturing has facilitated fabrication of complex and patient-specific metallic meta-biomaterials that offer an unprecedented collection of mechanical, mass transport, and biological properties as well as a fully interconnected porous structure.

Additive manufacturing

fabrication

metallic

as

as

mechanical

transport

properties

porous


Input: However, applying meta-biomaterials for addressing unmet clinical needs in orthopedic surgery requires additional surface functionalities that should be induced through tailor-made coatings.

surgery

coatings

surface

be


Input: Here, we developed multi-functional layer-by-layer coatings to simultaneously prevent implant-associated infections and stimulate bone tissue regeneration.

layer-by-layer

bone tissue regeneration

coatings


Input: We applied multiple layers of gelatin- and chitosan-based coatings containing either bone morphogenetic protein (BMP) -2 or vancomycin on the surface of selective laser melted porous structures made from commercial pure Titanium (CP Ti) and designed using a triply periodic minimal surface (i.e., sheet gyroid).

coatings

bone

surface

triply periodic minimal surface

selective laser melted

porous

Titanium

Ti

sheet

designed


Input: The additive manufacturing process resulted in a porous structure and met the the design values comparatively.

additive manufacturing process

porous

design


Input: X-ray photoelectron spectroscopy spectra confirmed the presence and composition of the coating layers.

X-ray photoelectron spectroscopy

composition

coating


Input: The osteogenic differentiation of mesenchymal stem cells was enhanced, as shown by two-fold increase in the alkaline phosphatase activity and up to four-fold increase in the mineralization of all experimental groups containing BMP-2.

mesenchymal stem cells

as

experimental


Input: Eight-week subcutaneous implantation in vivo showed no signs of a foreign body response, while connective tissue ingrowth was promoted by the layer-by-layer coating.

subcutaneous

implantation

layer-by-layer

coating


Input: These results unequivocally confirm the superior multi-functional performance of the developed biomaterials.

performance

biomaterials


Input: The feasibility of in situ quantitative multielemental analysis during additive manufacturing process has been demonstrated for the first time.

feasibility

in situ

additive manufacturing process


Input: The specially designed laser induced breakdown spectroscopy (LIBS) instrument was equipped the laser cladding head installed at an industrial robot.

designed

spectroscopy

laser cladding

industrial robot


Input: Melt pool surface sampling by LIBS probe was demonstrated to be the only choice for quantitative elemental analysis.

Melt pool

be

sampling

quantitative

probe

elemental analysis


Input: On-line LIBS quantitative analysis of carbon and tungsten has been demonstrated during the synthesis of wear resistant coatings.

quantitative

wear

carbon

tungsten

coatings


Input: Online LIBS results were in good agreement with offline analysis by conventional techniques (EDX, XRF and combustion infrared absorption method).

EDX

infrared absorption


Input: The feasibility of in situ quantitative multi-elemental analysis during the additive manufacturing process has been demonstrated for the first time using laser induced breakdown spectroscopy (LIBS).

feasibility

in situ

spectroscopy

additive manufacturing process

laser


Input: The coaxial laser cladding technique was utilized for the production of highly wear-resistant coatings (nickel alloy reinforced with tungsten carbide grains).

laser cladding

production

coatings

nickel alloy

tungsten carbide

grains


Input: High-quality production as well as gradient composition coating synthesis required an online technique for quantitative elemental analysis.

production

as

as

composition

quantitative

coating

elemental analysis


Input: A low-weight, compact LIBS probe was designed to equip the laser cladding head installed at an industrial robot.

compact

laser cladding

probe

industrial robot

designed


Input: Hot solidified clad as well as a melt pool surface was sampled by the LIBS probe but meaningful analytical results were achieved only for the latter case due to non-uniform distribution of tungsten carbide grains in the upper surface layer.

as

as

melt pool

tungsten carbide

probe

distribution

grains

surface

layer


Input: LIBS sampling inside the melt pool did not affect the clad properties according to optical microscopy and scanning electron microscopy measurements.

sampling

properties

melt pool

optical microscopy

scanning electron microscopy


Input: On-line LIBS quantitative analysis of key components (carbon and tungsten) was demonstrated during the synthesis of highly wear-resistant coatings and obtained results were in good agreement with offline analysis performed by electron energy dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy, and the combustion infrared absorption method.

quantitative

components

carbon

tungsten

coatings

energy dispersive X-ray spectroscopy

X-ray

fluorescence

infrared absorption


Input: In situ quantitative multielemental analysis by LIBS is a perspective control or/and feedback tool to improve quality of compositionally graded materials in additive manufacturing.

In situ

quality

materials

feedback

additive manufacturing


Input: Our objective herein is to investigate laser-based additive manufacturing to fabricate application-optimized machine-tools that perform comparably to commercially-available products.

laser-based additive manufacturing

fabricate


Input: To demonstrate this technology, multi-layer Stellite™ (Co-Cr-W superalloy) structures were deposited on a stainless-steel substrate via directed energy deposition technique to be used as a tool for cutting applications requiring high-temperature strength and ductility, an area where conventional carbide and high-speed steel tools are challenged.

technology

substrate

be

as

carbide

steel

directed energy deposition

cutting

tool

strength

ductility

area


Input: The as-printed structures were free of large-scale defects and voids, and were further characterized and compared to commercial Blackalloy 525 barstock (B525), a Co-Cr-W alloy tool of similar composition.

defects

voids

composition

alloy


Input: The Stellite™ contained mostly Co-rich (α-phase) dendrites, as well as inter-dendritic Cr7C3 and Cr23C6 phases.

dendrites

as

as


Input: The B525 composition consisted of a range of lamellar-eutectic microstructure comprised of Co-phase with W6C reinforcement.

composition

microstructure

range

reinforcement


Input: During a turning operation of SS304L, the Stellite™ 6 tool demonstrated consistent chip formation and more consistent rake-face and cratering wear in comparison to the B525 tool, indicating its adequacy for service in this application.

turning

tool

tool

chip

wear


Input: Our results demonstrate for the first time that directed-energy-deposition can be utilized to fabricate advanced cutting tool concepts for job-specific applications.

be

fabricate

cutting tool


Input: The influence of geometry and scan pattern on the microstructure evolution and magnetic performance of additively manufactured Fe-3Si components was investigated.

geometry

microstructure evolution

performance

scan pattern

additively manufactured

components


Input: To reduce eddy current losses, novel geometries were designed and built and the microstructure and properties of these samples were characterized.

geometries

microstructure

properties

samples

designed


Input: The laser scan pattern was shown to strongly influence both the as-built grain structure and strength of the crystallographic texture, resulting in measurable changes in the as-built magnetic performance.

laser scan

grain structure

performance

strength

texture


Input: In thin wall samples, heat treatment resulted in an increase in the maximum relative magnetic permeability and decrease in power losses in most samples, consistent with grain growth.

samples

samples

grain growth

heat treatment

permeability

power


Input: Compared to simple parallel plate construction and a mesh structure, a novel cross-section design based on the Hilbert space filling curve was found to produce the lowest power losses.

simple

construction

structure

design

power


Input: The mechanisms behind these results were explored using a combination of heat conduction and electromagnetic simulations, providing a route for future component and process optimization.

heat conduction

process optimization

simulations

component


Input: In this study, a laser-based additive manufacturing route of selective laser melting (SLM) was applied to fabricate carbon nanotubes (CNTs) reinforced Al-based nanocomposites with tailored microstructures and excellent mechanical properties.

laser-based additive manufacturing

selective laser melting

SLM

fabricate

carbon nanotubes

CNTs

microstructures

reinforced

mechanical properties


Input: The densification behavior, microstructure features and mechanical properties were investigated and the relationship between process and property was established.

densification

microstructure

mechanical properties

process

property


Input: The results showed that the applied laser power and scan speed were the governing factors of the densification behavior of SLM-processed Al-based nanocomposites.

laser power

scan speed

densification


Input: SLM processing of 0.5 wt.% CNTs/AlSi10Mg nanocomposite powder led to the formation of three typical microstructures including the primary Al9Si cellular dendrites decorated with fibrous Si, the in situ Al4C3 covered on CNTs, and the precipitated Si inside the cellular grains.

SLM

powder

microstructures

CNTs

Si

led

dendrites

fibrous

in situ

cellular grains


Input: As the optimal SLM processing parameters of laser power of 350 W and scan speed of 2.0 m/s were applied, the fully dense SLM-processed CNTs/Al-based nanocomposites exhibited high microhardness of 154.12 HV0.2, tensile strength of 420.8 MPa and elongation of 8.87%, due to the formation of high densification and ultrafine microstructure.

As

SLM

densification

parameters

microhardness

MPa

microstructure

laser power

scan speed

fully dense

tensile strength

elongation


Input: The grain refinement effect, Orowan looping system and load transfer are considered as three strengthening mechanisms occurred simultaneously during tensile tests, leading to excellent mechanical properties of SLM-processed CNTs/Al-based nanocomposites.

grain refinement

tensile tests

Orowan looping

strengthening mechanisms

mechanical properties

as


Input: A skeleton sand mold which includes lattice-shell type, rib enforced type and air pockets structure was presented.

sand

mold

structure


Input: These sand molds can save mold sand and control the time of casting.

sand

molds

mold

casting


Input: These sand molds make it possible to adjust the cooling and solidification conditions of castings.

sand

molds

cooling

solidification


Input: These sand molds can improve production efficiency, and reduce deformation, residual stress and defects of castings.

sand

molds

production

deformation

defects

residual stress


Input: The advance of additive manufacturing drives the design of molds for castings.

additive manufacturing

design

molds


Input: The shell forms the cavity for a casting and the surrounding ribs or lattices support and enforce the shell.

shell

shell

casting

lattices


Input: This type of mold structure design results in fast and uniform cooling of a casting, which can improve production efficiency and reduce the deformation and residual stress of a casting.

mold

design

cooling

casting

production

casting

deformation

residual stress


Input: In addition, it provides more space and flexibility to adjust the cooling conditions of interested locations of a casting.

flexibility

cooling

casting


Input: The thickness of the shell can be varied according to the local geometries of a casting.

shell

be

geometries

casting


Input: The support is designed based on the hydrostatic pressure before solidification and the weight after solidification.

support

designed

hydrostatic pressure

weight

solidification

solidification


Input: An air pocket (hollow structure) in the shell was designed for the riser to postpone its solidification and then facilitate shrinkage feeding.

structure

solidification

shrinkage

shell

riser

designed


Input: The experimental results revealed that the new design of sand molds saved at least 60% sand and shortened the shakeout time by at least 20%.

experimental

design

sand

sand

molds


Input: Local hollow structure prolonged its solidification process by approximately 15%.

structure

solidification process


Input: For the first time, a method of comparing quantitatively measurement apparatus for additive manufacture is defined.

quantitatively measurement

additive manufacture


Input: Novel instrumentation is subject to this analysis by way of case studies.

case studies


Input: Results allow researchers and industrial users alike to quickly assess the compatibility of an NDE technique with additive manufacturing processes.

industrial

additive manufacturing processes


Input: Cs and Ct, the spatial and temporal capability, respectively, are shown to be useful analysis methods for integration feasibility efforts.

Ct

be

feasibility


Input: Unlike more established subtractive or constant volume manufacturing technologies, additive manufacturing methods suffer from a lack of in-situ monitoring methodologies which can provide information relating to process performance and the formation of defects.

subtractive

manufacturing technologies

additive manufacturing

volume

in-situ

process performance

defects


Input: In-process evaluation for additive manufacturing is becoming increasingly important in order to assure the integrity of parts produced in this way.

additive manufacturing

integrity


Input: This paper addresses the generic performance of inspection methods suitable for additive manufacturing.

performance

inspection

additive manufacturing


Input: Key process and measurement parameters are explored and the impacts these have upon production rates are defined.

process

measurement

production


Input: A new method of benchmarking in-situ inspection instruments and characterising their suitability for additive manufacturing processes is presented to act as a design tool to accommodate end user requirements.

in-situ

additive manufacturing processes

as

design


Input: Two inspection examples are presented: spatially resolved acoustic spectroscopy and optical coherence tomography for scanning selective laser melting and selective laser sintering parts, respectively.

inspection

optical

spectroscopy

scanning

laser

selective laser sintering


Input: Observations made from the analyses presented show that the spatial capability arising from scanning parameters affects the temporal penalty and hence impact upon production rates.

scanning parameters

impact

production


Input: A case study, created from simulated data, has been used to outline the spatial performance of a generic nondestructive evaluation method and to show how a decrease in data capture resolution reduces the accuracy of measurement.

case study

data

performance

data

resolution

accuracy

measurement


Input: While copper is a potent strengthener in titanium alloys, its use in commercial alloys has been severely restricted due to the strong tendency for segregation during solidification, leading to heterogeneous microstructures and what has often been referred to as the “beta-fleck” problem.

copper

titanium alloys

alloys

as

segregation

solidification

heterogeneous


Input: This problem can be largely obviated by using additive manufacturing (AM) for processing Ti-Cu alloys.

be

alloys

additive manufacturing

AM


Input: This study focuses on AM of a binary Ti-4Cu and a ternary Ti-4Cu-4Al alloy using the laser engineered net shaping (LENS) process.

AM

laser engineered net shaping

LENS

binary

process

alloy


Input: The influence of post-deposition annealing treatments and the subsequent cooling rate on the microstructure and tensile properties of these alloys has been investigated in detail.

annealing treatments

cooling rate

microstructure

tensile properties

alloys


Input: The phase fraction of the eutectoid alpha + Ti2Cu product is dependent on the cooling rate from above the beta transus temperature.

phase fraction

eutectoid

cooling rate

temperature


Input: Additionally, the Ti2Cu phase exhibited a far-from equilibrium composition in case of the water-quenched Ti-4Cu-4Al alloy.

phase

equilibrium composition

alloy


Input: Both the yield stress (∼550−650 MPa) as well as the ductility (∼15–18%) were also higher in case of the ternary alloy.

yield stress

ductility

MPa

as

as

ternary alloy


Input: The high strengths exhibited by the water-quenched samples of both alloys, while maintaining appreciable tensile ductility, could be attributed to clustering of Cu within the α laths, revealed by atom probe tomography.

strengths

tensile ductility

samples

alloys

be

Cu

atom probe tomography


Input: Powder bed fusion additive manufacturing (AM) technology, such as electron beam melting (EBM) and selective laser melting, has attracted tremendous academic and industrial interests because of its capacity to fabricate components with greater complexity compared with traditional processes, without significantly increasing the cost.

Powder bed fusion additive manufacturing

AM

EBM

selective laser melting

fabricate

technology

capacity

complexity

processes

as

beam

components

industrial


Input: It provides significantly higher design freedom to the designers and can make the built components closer to the optimum design in theory when compared with traditional processes.

design freedom

processes

components

design


Input: However, the mechanical performance of the new design fabricated by AM has not been clarified yet.

mechanical

design

AM


Input: Here, we report the fabrication and tensile deformation behavior of the EBM-built lightweight car suspension double wishbone for both conventional and optimized designs.

fabrication

tensile

deformation

lightweight

car

designs


Input: EBM process is an effective method to produce a highly-dense Ti-6Al-4V lightweight design component with good reproducibility and fine α/β duplex microstructure.

EBM

lightweight

reproducibility

microstructure

design

component


Input: A poor mechanical performance in the optimized design is observed, which results from the build thickness-dependent mechanical performance that is caused by both various microstructures and rough surfaces in the Ti-6Al-4V parts.

mechanical

mechanical

design

build

microstructures

surfaces


Input: Notably, the rough surface plays a dominant role in premature failure when the build thickness is below 2 mm.

surface

failure

build

mm


Input: Based on these findings, the degraded mechanical performance in the optimized design is discussed.

mechanical

design


Input: The experimental results and analyses provide a guideline for the design of lightweight structures that are mainly comprised of thin walls and/or struts.

experimental

design

lightweight structures

struts


Input: Additive manufacturing (AM) allows engineers to design and manufacture complex weight saving lattice structures with relative ease.

Additive manufacturing

AM

design

lattice structures

manufacture

weight


Input: A non-destructive testing and evaluation method used to assess material properties and quality is the focus of this paper, namely acoustic resonance (AR) testing.

non-destructive testing

testing

material properties

quality

AR


Input: For this research, AR testing was conducted on weight saving lattice structures (fine and coarse) manufactured by powder bed fusion.

research

manufactured

AR

weight

lattice structures

powder bed fusion


Input: The suitability of AR testing was assessed through a combined approach of experimental testing and FE modelling.

AR

experimental

FE


Input: A sensitivity study was conducted on the FE model to quantify the influence of element coarseness on the resonant frequency prediction and this needs to be taken into account in the application and analysis of the technique.

sensitivity

FE

element

be

prediction


Input: The AR and FE modelling modulus of elasticity values were validated using specimens of known properties.

AR

FE

modulus of elasticity

properties


Input: There was fair agreement between the FE and compression test extracted values of effective modulus for the coarse lattice.

FE

compression test

lattice


Input: For the fine lattice, there was agreement in the values of effective modulus extracted from AR, 3-point bend, and compression experimental tests carried out.

lattice

extracted

AR

compression


Input: It was found that loose powder fusing from AM resulted in the fine lattice structure having a higher density (at least 1.5 times greater) than calculated due to the effect of loose powder adhesion.

powder

powder

fusing

AM

lattice structure

density

adhesion


Input: This effect resulted in an increased stiffness of the fine lattice structure.

stiffness

lattice structure


Input: AR can be used as a measure of determining loose powder adhesion and other unique structural characteristics resulting from AM.

AR

be

as

powder

adhesion

AM


Input: Increasing performance requirements of advanced components demands versatile fabrication techniques to meet application-specific needs.

performance

components

fabrication


Input: Composite material processing via laser-based additive manufacturing offers high processing-flexibility and limited tooling requirements to meet this need, but limited information exists on the processing-property relationships for these materials as well as how to exploit them for application-specific needs.

Composite material

as

as

laser-based additive manufacturing

tooling

materials


Input: In this study, Ti/B4C + BN composites are developed for high-temperature applications by designed-incorporation of ceramic reinforcement (5 wt% total) into commercially-pure titanium to form combined particle and in situ reinforcing phases.

BN

ceramic reinforcement

titanium

particle

in situ


Input: We combine both B4C (limited reactivity with matrix) and BN (high reactivity with matrix) reinforcements to understand the processing characteristics, in situ phase formations, and combinatorial effect of the multiphase microstructures on thermomechanical properties and high-temperature oxidation resistance.

BN

microstructures

in situ

thermomechanical properties

oxidation resistance


Input: Combined reinforcement in this new composite material leads to superior yield strength and wear resistance in comparison to the other compositions and matrix, as well as comparable oxidation characteristics to commercially-developed high temperature titanium alloys, alleviating the need for multiple rare-earth alloying elements that significantly raises costs for manufacturers.

reinforcement

temperature

composite material

as

as

alloys

alloying elements

yield strength

wear resistance

oxidation


Input: Tubular structures are fabricated to demonstrate the ease of site-specific composition and dimensional tolerancing using this method.

Tubular

fabricated

composition


Input: Our results indicate that tailored ceramic reinforcement in titanium via laser-based AM could lead to significantly enhanced engineering structures, particularly for developing higher temperature titanium-based materials.

ceramic reinforcement

titanium

lead

AM

engineering

temperature

materials


Input: Previous research on the powder bed fusion electron beam additive manufacturing of Inconel 718 has established a definite correlation between the processing conditions and the solidification microstructure of components.

research

solidification microstructure

powder bed fusion electron beam additive manufacturing

Inconel 718

components


Input: However, the direct role of physical phenomena such as fluid flow and vaporization on determining the solidification morphology have not been investigated quantitatively.

as

solidification morphology

quantitatively


Input: Here we investigate the transient and spatial evolution of the fusion zone geometry, temperature gradients, and solidification growth rates during pulsed electron beam melting of the powder bed with a focus on the role of key physical phenomena.

transient

evolution

fusion zone

solidification

temperature gradients

electron beam melting

powder bed


Input: The effect of spot density during pulsing, which relates to the amount of heating of the build area during processing, on the columnar-to-equiaxed transition of the solidification structure was studied both experimentally and theoretically.

density

heating

build area

transition

solidification


Input: Predictions and the evaluation of the role of heat transfer and fluid flow were established using existing solidification theories combined with transient, three-dimensional numerical heat transfer and fluid flow modeling.

Predictions

heat transfer

solidification

transient

three-dimensional

heat transfer

fluid flow

fluid flow


Input: Metallurgical characteristics of the alloy’ s solidification are extracted from the transient temperature fields, and microstructure is predicted and validated using optical images and electron backscattered diffraction data from the experimental results.

Metallurgical

alloy

s

extracted

transient

microstructure

predicted

images

data

experimental

temperature

optical

diffraction


Input: While conductive heat transfer dominates in the mushy region, both the pool geometry and the solidification parameters are affected by convective heat transfer.

conductive heat transfer

geometry

solidification parameters

heat transfer


Input: Finally, increased spot density during processing is shown to increase the time of solidification, lowering temperature gradients and increasing the probability of equiaxed grain formation.

density

solidification

probability

equiaxed grain

temperature gradients


Input: In this paper we have used laser powder bed fusion (PBF) to manufacture and characterize metal microwave components.

laser powder bed fusion

PBF

manufacture

metal

components


Input: Here we focus on a 2.5 GHz microwave cavity resonator, manufactured by PBF from the alloy AlSi10Mg.

microwave

resonator

manufactured

PBF

alloy


Input: Of particular interest is its thermal expansion coefficient, especially since many microwave applications for PBF produced components will be in satellite systems where extreme ranges of temperature are experienced.

thermal expansion coefficient

microwave

PBF

components

be

temperature


Input: We exploit the inherent resonant frequency dependence on cavity geometry, using a number of TM cavity modes, to determine the thermal expansion coefficient over the temperature range 6–450 K. Our results compare well with literature values and show that the material under test exhibits lower thermal expansion when compared with a bulk aluminium alloy alternative (6063).

geometry

thermal expansion

thermal expansion coefficient

temperature range

material

aluminium alloy


Input: Metal additive manufacturing is an emerging method to fabricate components used in the aerospace and biomedical industries.

Metal additive manufacturing

fabricate

components

aerospace

biomedical industries


Input: However, one of the significant challenges in this approach is the surface quality of the fabricated components.

surface quality

fabricated

components


Input: After metal additive manufacturing operations, post-processing is essential to meet the expected surface quality.

metal additive manufacturing

post-processing

surface quality


Input: This study presents the surface characteristics of as-built specimens manufactured by selective laser melting (SLM), where improvement of the surface can be achieved by post-processing operations.

surface

manufactured

surface

post-processing

selective laser melting

SLM

be


Input: The post-processing operations in focus are finish machining (FM), vibratory surface finishing (VSF) and drag finishing (DF) operations.

post-processing

finish machining

surface finishing

drag


Input: Surface topography, average surface roughness, microhardness, microstructure and XRD analysis have been carried out to examine the surface characteristics resulting from the post-processing operations.

Surface topography

average

microhardness

microstructure

surface

post-processing

roughness

XRD


Input: This study demonstrates that the drag finishing operation can be used for post-processing to meet the surface quality requirement of SLM manufactured parts.

drag

be

post-processing

manufactured

surface quality

SLM


Input: In-process deformation methods such as rolling can be used to refine the large columnar grains that form when wire + arc additively manufacturing (WAAM) titanium alloys.

deformation

as

be

titanium alloys

columnar grains

wire + arc additively manufacturing

WAAM


Input: Due to the laterally restrained geometry, application to thick walls and intersecting features required the development of a new ‘inverted profile’ roller.

geometry

profile

roller


Input: A larger radii roller increased the extent of the recrystallised area, providing a more uniform grain size, and higher loads increased the amount of refinement.

roller

area

grain size


Input: Electron backscatter diffraction showed that the majority of the strain is generated toward the edges of the rolled groove, up to 3 mm below the rolled surface.

Electron backscatter diffraction

strain

mm

surface


Input: These results will help facilitate future optimisation of the rolling process and industrialisation of WAAM for large-scale titanium components.

rolling process

WAAM

titanium

components