Input: The absorption of energy by these particles in laser directed energy deposition additive manufacturing was calculated using the proposed model, which was validated experimentally.

absorption

particles

model

laser directed energy deposition additive manufacturing


Input: Both numerical model and experiment were used to study the effects of powder velocities on the temperature variations in the additive manufacturing process.

model

experiment

powder

temperature

additive manufacturing process


Input: Results indicate that the direct heat transfer from the laser to a target can be increased if the size distribution is wider; it also increases with the velocity of the particles.

heat transfer

distribution

particles

laser

be


Input: However, with the increase of powder-flow rate, the rate of mass transfer decreases the heat transfer.

heat transfer


Input: Melt-pool depth in melting and re-melting processes can therefore be controlled by varying these parameters.

melting

processes

parameters

be


Input: Wire‐arc additive manufacturing is a metal additive manufacturing process that enables the production of large components at a high deposition rate.

additive manufacturing

metal additive manufacturing

production

components

high deposition rate


Input: This process transfers a large amount of heat to the workpiece, requiring the introduction of idle times between the deposition of subsequent layers so that the workpiece cools down.

process

heat

workpiece

deposition

workpiece


Input: This procedure prevents the workpiece from collapsing and ensures a suitable interpass temperature.

workpiece

interpass temperature


Input: The main challenge is the selection of such an idle time capable of ensuring the required interpass temperature, because the cooling rate of the workpiece changes throughout the process, entailing the need for a different idle time between the deposition of subsequent layers to achieve a constant interpass temperature.This paper proposes an innovative approach to schedule the deposition of interlayer idle times for wire‐arc additive manufacturing process.

interpass temperature

cooling rate

interpass

workpiece

process

deposition

deposition

additive manufacturing process


Input: The technique is based on a finite element analysis of the thermal behavior of the workpiece, by solving the heat transfer equations.

finite element analysis

workpiece

heat transfer


Input: The simulation data are processed using the developed algorithm to compute specific idle times for the deposition of each layer, thereby ensuring a constant interpass temperature.

simulation

data

processed

algorithm

deposition

layer

interpass temperature


Input: The effectiveness of the proposed technique is validated by experiments performed on a test case component.

effectiveness

component


Input: The temperature data measured during the process are compared with the FE simulation results to verify the accuracy of the model.

temperature

data

process

model

FE

accuracy


Input: There is a growing interest in using recycled materials and economically produced powder in additive manufacturing processes.

recycled materials

powder

additive manufacturing processes


Input: State-of-the-art powder bed fusion additive manufacturing processes typically use spherical powder that are produced using an atomization process.

State-of-the-art

spherical

powder bed fusion additive manufacturing

atomization

powder


Input: However, using irregularly shaped Ti-6Al-4V powder from the Hydride-Dehydride (HDH) process is more economical because fewer processing steps are required and it can use recycled material as feedstock.

Ti-6Al-4V powder

as

process

recycled material


Input: In this work, the use of HDH powder in the electron beam additive manufacturing (EBAM) process is investigated.

powder

electron beam additive manufacturing

EBAM

process


Input: Deposition parameters for the HDH powder were developed, followed by a detailed study of as-built porosity and microstructure.

Deposition

microstructure

powder

porosity


Input: The powder flow characteristics were also studied, and the as-built part porosity was compared to the parts built using spherical atomized powder.

powder

porosity

spherical

atomized


Input: This work demonstrates the successful use of non-spherical HDH powder in the EBAM process.

non-spherical

powder

EBAM


Input: The extension of metal additive manufacturing (AM) to non-weldable Ni-based superalloys remains a challenge for the electron beam melting process.

metal additive manufacturing

AM

electron beam melting

superalloys


Input: Various cracking mechanisms, including solidification, liquation, strain-age, and ductility dip cracking, make it difficult to fabricate traditionally non-weldable Ni-based superalloys using the AM process.

cracking

solidification

cracking

ductility

fabricate

AM process

superalloys


Input: Because airfoil geometries are highly complicated, the correspondingly complex thermal signatures lead to various types of cracking in geometries that are under severe mechanical restraints during the printing process.

geometries

cracking

geometries

lead

mechanical

printing process


Input: This work aims to understand the correlations between cracking, scan strategy, and part geometry in airfoil geometries.

cracking

geometry

geometries


Input: Crack locations were monitored via an in-situ near-infrared camera during printing.

in-situ

camera


Input: A part-scale finite element method (FEM) was used to reveal cracking mechanisms.

finite element method

FEM

cracking


Input: New scan strategies that avoided cracking were utilized in an FEM simulation.

cracking

FEM


Input: The present work demonstrates the potential for scan strategy optimization to manipulate stress distribution and the resultant microstructure of parts for industrial applications.

optimization

microstructure

stress distribution

industrial


Input: Recent work in metal additive manufacturing (AM) suggests that mechanical properties may vary with feature size; however, these studies do not provide a statistically robust description of this phenomenon, nor do they provide a clear causal mechanism.

metal additive manufacturing

AM

mechanical properties

mechanism

feature size


Input: Because of the huge design freedom afforded by 3D printing, AM parts typically contain a range of feature sizes, with particular interest in smaller features, so the size effect must be well understood in order to make informed design decisions.

design freedom

size effect

3D printing

AM parts

range

feature sizes

be

design


Input: This work investigates the effect of feature size on the stochastic mechanical performance of laser powder bed fusion tensile specimens.

investigates

stochastic

feature size

mechanical

laser powder bed fusion


Input: A high-throughput tensile testing method was used to characterize the effect of specimen size on strength, elastic modulus and elongation in a statistically meaningful way.

tensile testing

strength

elastic modulus

elongation


Input: The effective yield strength, ultimate tensile strength and modulus decreased strongly with decreasing specimen size: all three properties were reduced by nearly a factor of two as feature dimensions were scaled down from 6.25 mm to 0.4 mm.

yield strength

ultimate tensile strength

properties

as

dimensions

mm

mm


Input: Hardness and microstructural observations indicate that this size dependence was not due to an intrinsic change in material properties, but instead the effects of surface roughness on the geometry of the specimens.

Hardness

surface roughness

microstructural observations

material properties

geometry


Input: Finite element analysis using explicit representations of surface topography shows the critical role surface features play in creating stress concentrations that trigger deformation and subsequent fracture.

Finite element analysis

surface topography

surface

deformation

fracture

stress concentrations


Input: The experimental and finite element results provide the tools needed to make corrections in the design process to more accurately predict the performance of AM components.

experimental

finite element

design process

performance

tools

accurately

AM


Input: A hybrid manufacturing supply chain based on metal Additive Manufacturing (AM) is proposed.

hybrid manufacturing

metal Additive Manufacturing

AM


Input: Adding capacity to existing AM hubs is preferred over establishing new AM hubs at current demand.

capacity

AM

AM


Input: The ever-growing applications of Additive Manufacturing (AM) in the production of low volume- high value metal parts can be attributed to improving AM processing capabilities and complex design freedom.

Additive Manufacturing

AM

production

AM

metal

be

design freedom


Input: However, secondary post-processing using traditional processes such as machining, grinding, heat treatment and hot isostatic pressing, i.e., Hybrid Manufacturing, is required to achieve Geometric Dimensioning and Tolerancing (GD & T), surface finish and desired mechanical properties.

post-processing

processes

Hybrid Manufacturing

Geometric Dimensioning

mechanical properties

as

GD

grinding

heat treatment

hot isostatic pressing

surface finish


Input: It is often challenging for most traditional manufacturers to participate in the rapidly evolving supply chain of direct digital manufacturing (DDM) through in-house investments in cost prohibitive metal AM.

supply chain

DDM

direct digital manufacturing

metal AM


Input: This research investigates a system of strategically-located AM hubs which can integrate hybrid-AM with the capabilities and excess capacity in multiple traditional manufacturing facilities.

research investigates

capacity

AM

traditional manufacturing


Input: Using North American Industry Classification System (NAICS) data for machine shops in the U.S., an uncapacitated facility location model is used to determine the optimal locations for AM hub centers based on: (1) geographical data, (2) demand and (3) cost of hybrid-AM processing.

Industry

Classification

data

model

data

machine

AM


Input: Results from this study have identified: (a) candidate US counties to build AM hubs, (b) total cost (fixed, operational and transportation) and (c) capacity utilization of the AM hubs.

build

AM

AM

b

c

capacity


Input: It was found that uncapacitated facility location models identified demand centroid as the optimal location and was affected only by AM utilization rate whereas a constrained p-median model identified 22 AM hub locations as the initial sites for AM hubs which grows to 44 AM hubs as demand increases.

as

as

as

AM

AM

AM

AM

model


Input: It was also found that transportation cost was not a significant factor in the hybrid-AM supply chain.

supply chain


Input: Findings from this study will help both AM companies and traditional manufacturers to determine location in the U.S and key factors to advance the metal hybrid-AM supply chain.

AM

metal

supply chain


Input: In this paper, maraging steel powder was deposited on top of an H13 tool steel using laser powder bed fusion (LPBF) technique.

maraging steel

H13 tool steel

laser powder bed fusion

LPBF


Input: The mechanical properties, microstructure, and interfacial characteristics of the additively manufactured MS1-H13 bimetals were investigated using different mechanical and microstructural techniques.

mechanical properties

microstructure

microstructural

additively manufactured

mechanical


Input: Several uniaxial tensile tests and micro-hardness indentations were performed to identify the mechanical properties of the additively manufactured bimetal.

tensile tests

mechanical properties

additively manufactured


Input: Advanced electron microscopy techniques including electron backscatter diffraction and transmission electron microscopy were used to identify the mechanism of interface formation.

electron microscopy

electron backscatter diffraction

transmission electron microscopy

mechanism

interface


Input: In addition, the microstructure of the additively manufactured maraging steel along with the conventionally fabricated substrate-H13 were studied.

microstructure

fabricated

additively manufactured

steel


Input: It was concluded that, a very narrow interface was formed between the additively manufactured maraging steel and the conventional H13 without forming cracks or discontinuities.

interface

additively manufactured

forming

steel


Input: The first deposited layers possessed the highest hardness due to grain size refinement, solid solution strengthening, and cellular solidification structure.

deposited layers

hardness

grain size

solid solution

solidification


Input: Finally, under uniaxial tensile loading, the additively manufactured bimetal steel failed from the underlying tool steel, indicating a robust interface.

tensile

additively manufactured

steel

steel

tool

interface


Input: Thermomechanical analyses of WAAM by implicit FEM and explicit FEM were compared.

Thermomechanical

FEM

FEM

WAAM


Input: Explicit FEM can be greatly accelerated (30,000×) using time scaling technique.

FEM

be


Input: Real-time simulation of WAAM was achieved for a large-scale build (500 × 40 × 5 mm3).

simulation

WAAM

build


Input: Developed FEMs all showed high accuracy in predicting residual stress and distortion.

accuracy

residual stress

distortion


Input: This study aims to advance the structural analysis of wire and arc additive manufacturing (WAAM) by considering the thermomechanical features inherent in direct energy deposition.

structural analysis

wire and arc additive manufacturing

WAAM

direct energy deposition

thermomechanical


Input: Simulation approaches including the iterative substructure method (ISM), dynamic mesh refining method (DMRM), and graphics processing unit (GPU) based explicit finite element method (FEM) were developed for accelerating additive manufacturing stress analysis that is very time consuming by conventional numerical methods.

Simulation

dynamic

finite element method

FEM

additive manufacturing


Input: The residual stress and distortion of two large builds were analyzed, showing very consistent numerical results and good agreement with experiments.

residual stress

distortion

builds


Input: Compared with the commercial software Abaqus, the novel approaches reduced the computational cost substantially without compromising accuracy.

software

Abaqus

accuracy


Input: Such high-fidelity modeling approaches will be very useful for building up a digital twin of WAAM to reduce development time and cost.

high-fidelity

be

WAAM


Input: WAAM (Wire-Arc-Additive-Manufacturing) is a metal additive manufacturing process using arc welding to create large components with high deposition rate.

WAAM

metal additive manufacturing

arc welding

components

high deposition rate


Input: The workpiece quality and the process productivity are strongly dependent both on the process parameters (wire feed speed, voltage and current) and on the selected deposition path.

workpiece quality

process

process parameters

feed

deposition path


Input: Currently, the CAM (Computer-Aided-Manufacturing) software dedicated to WAAM rely on a multi-pass strategy to create the component layers, i.e.

CAM

software

WAAM

component


Input: each layer is built overlapping multiple welding passes.

layer

welding


Input: However, since WAAM can create wide layers, a single pass strategy can improve the process efficiency when dealing with thin walled components.

WAAM

process

components


Input: This paper proposes CAM software dedicated to WAAM, using a single pass strategy.

CAM

WAAM


Input: The proposed solution uses a midsurface representation of the workpiece as input, to generate the deposition toolpath.

solution

workpiece

deposition

as


Input: A specific strategy is developed and proposed for each one of the selected features, with the aim of minimizing the geometrical errors and to ensure the required machining allowances for the subsequent finishing operations.

errors

machining allowances

finishing operations


Input: The effectiveness of the proposed strategy is verified manufacturing a test case.

effectiveness

manufacturing


Input: The Wire-Arc Additive Manufacturing (WAAM) process is an increasingly attractive method for producing porosity-free metal components.

Wire-Arc Additive Manufacturing

WAAM

process

metal

components


Input: However, the residual stresses and distortions resulting from the WAAM process are major concerns as they not only influence the part tolerance but can also cause premature failure in the final component during service.

residual stresses

WAAM

process

failure

as

tolerance

component


Input: The current paper presents a method for using neutron diffraction to measure residual stresses in Fe3Al intermetallic wall components that have been in-situ additively fabricated using the WAAM process with different post-production treatments.

neutron diffraction

residual stresses

intermetallic

components

in-situ

fabricated

process

WAAM


Input: By using averaging methods during the experimental setup and data processing, more reliable residual stress results are obtained from the acquired neutron diffraction data.

experimental

data

data

residual stress

neutron diffraction


Input: In addition, the present study indicates that the normal residual stresses are significant compared to normal butt/fillet welding samples, which is caused by the large temperature gradient in this direction during the additive layer depositions.

residual stresses

welding

samples

temperature gradient

additive


Input: Additive Manufacturing (AM) presents unprecedented opportunities to enable design freedom in parts that are unachievable via conventional manufacturing.

Additive Manufacturing

AM

conventional manufacturing

design freedom


Input: However, AM-processed components generally lack the necessary performance metrics for widespread commercial adoption.

components

performance


Input: We present a novel AM processing and design approach using removable heat sink artifacts to tailor the mechanical properties of traditionally low strength and low ductility alloys.

AM

design

heat sink

mechanical properties

strength

ductility

alloys


Input: The design approach is demonstrated with the Fe-50 at.% Co alloy, as a model material of interest for electromagnetic applications.

design

Co

alloy

as

model material


Input: AM-processed components exhibited unprecedented performance, with a 300% increase in strength and an order-of-magnitude improvement in ductility relative to conventional wrought material.

components

performance

strength

ductility

wrought material


Input: These results are discussed in the context of product performance, production yield, and manufacturing implications toward enabling the design and processing of high-performance, next-generation components, and alloys.

performance

production

manufacturing

design

components

alloys


Input: Rib-web structures are used for lightweight design in various applications.

lightweight

design


Input: The most prominent cases are found in aerospace engineering, where intricate structures are produced by forging and subsequent machining or by machining from solid blocks of material.

aerospace

forging

machining

machining

material


Input: Due to the large scrap rate involved in conventional manufacturing, rib-web structures are suitable applications for additive manufacturing (AM) processes.

conventional manufacturing

additive manufacturing

AM

processes


Input: Among the AM processes, wire-arc additive manufacturing (WAAM) is highly suitable for rib-web structures due to its high deposition rate and the potential to manufacture large-size parts.

AM processes

wire-arc additive manufacturing

WAAM

high deposition rate

manufacture


Input: In WAAM, the welding strategy greatly influences the properties and quality of deposited parts.

WAAM

welding

properties

quality


Input: With an increasing number of starts and stops, the danger of uneven material build-up and welding defects increases.

material

welding defects


Input: This study presents a novel strategy for generating optimal tool paths for WAAM of lightweight rib-web structures, mitigating the disadvantages of discontinuous welding paths such as welding defects and uneven build-up.

tool paths

lightweight

defects

WAAM

welding

as


Input: When two or more weld beads are deposited on each edge, the vertices of the rib-web structure may suffer from underfilling.

weld beads

structure

vertices


Input: It is shown that this can be avoided by a correction strategy, which consists in manufacturing the part once, evaluating the size of voids in the junctions, and computing a correction to deposit the required amount of material into the center of the junction.

be

material

manufacturing

voids

junctions

junction


Input: While this strategy may be used if a single part is considered, it is shown that the tool path correction to be applied to arbitrary junction geometries can be represented by a neural network that is derived from an experimental database consisting of representative junction types.

be

be

be

tool path

geometries

neural network

experimental

junction

junction

database


Input: With this approach, paths for any rib-web geometry can be generated, which saves lead time in variant-rich production.

geometry

be

lead time

production


Input: Locally dispensing fine and irregular dry powders with a stable and continuous flow rate for additive manufacturing purposes is challenging.

powders

flow rate

additive manufacturing


Input: Ultrasonic vibration is an effective tool to deposit spherical powders.

Ultrasonic vibration

tool

spherical

powders


Input: However, the existing single ultrasonic vibration actuated powder dispenser could cause powder jamming and blockage when dispensing irregularly shaped ceramic particles.

ultrasonic vibration

powder

powder

ceramic


Input: In this study, we demonstrate a hybrid ultrasonic and motor vibration integrated dispensing method to successfully deposit irregularly shaped silicon carbide (SiC) powder and SiC and metal powder mixtures.

silicon carbide

SiC

powder

SiC

metal powder


Input: Flow rate experiments on mixed SiC-316 L powders with SiC volume fractions of 25 vol%, 40 vol%, and 50 vol%, indicated that the powder flow rate was determined by powder packing density after pre-mixing and before deposition.

Flow rate

powder flow rate

powders

SiC

powder

density

deposition


Input: A lower packing density resulted in a higher powder flow rate.

density

powder flow rate


Input: Both the SiC particle size and SiC volume fraction affected the final mixed powder packing density.

SiC

SiC

powder

particle

fraction

density


Input: The SiC-316 L mixture with 40 vol% of 320 grit SiC powder had the highest powder flow rate (37.53 μL/s).

SiC powder

powder flow rate


Input: Finally, the new powder deposition approach was successfully used for laser powder bed fusion manufacturing of a double helix structure made of a 316 L stainless steel and a SiC-316 L mixture.

powder

stainless steel

deposition

structure

laser powder bed fusion


Input: Such a powder dispensing technology has the potential to be applied in powder materials involved in additive manufacturing and pharmacy industries.

powder

be

powder materials

technology

additive manufacturing

industries


Input: Direct observation and quantification of melt pool evolution during LPBF through in-situ x-ray imaging.

melt pool

evolution

in-situ

LPBF

imaging


Input: Melt pool undergoes different melt regimes and exhibits orders-of-magnitude volume change under a constant input energy density.

Melt pool

melt

volume

energy density


Input: Laser absorption variation under constant input energy density is an important cause of melt pool variation.

Laser

absorption

energy density

melt pool


Input: Laser absorption variation stems from the separate effects of laser power and scan speed on depression zone development.

Laser

absorption

laser power

scan speed


Input: Size and shape of a melt pool play a critical role in determining the microstructure in additively manufactured metals.

melt pool

microstructure

additively manufactured


Input: However, it is very challenging to directly characterize the size and shape of the melt pool beneath the surface of the melt pool during the additive manufacturing process.

melt pool

melt pool

surface

additive manufacturing process


Input: Here, we report the direct observation and quantification of melt pool variation during the laser powder bed fusion (LPBF) additive manufacturing process under constant input energy density by in-situ high-speed high-energy x-ray imaging.

melt pool

laser powder bed fusion

LPBF

additive manufacturing process

energy density

in-situ

x-ray imaging


Input: We show that the melt pool can undergo different melting regimes and both the melt pool dimension and melt pool volume can have orders-of-magnitude change under a constant input energy density.

melt pool

melt pool

melting

melt pool dimension

energy density


Input: Our analysis shows that the significant melt pool variation can not be solely explained by the energy dissipation rate.

melt pool

be


Input: We found that energy absorption changes significantly under a constant input energy density, which is another important cause of melt pool variation.

energy absorption

energy density

melt pool


Input: Our further analysis reveals that the significant change in energy absorption originates from the separate roles of laser power and scan speed in depression zone development.

energy absorption

laser power

scan speed


Input: The results reported here are important for understanding the laser powder bed fusion additive manufacturing process and guiding the development of better metrics for processing parameter design.

laser powder bed fusion additive manufacturing process

parameter

design


Input: Successful round robin test conducted using various additive manufactured part producers of the same test parts.

round robin test

additive manufactured part


Input: Various intentional and unintentional defects identified.

defects


Input: Porosity/defect distribution extends from coupon samples to complex parts in general.

distribution

samples


Input: Micro computed tomography (microCT) allows non-destructive insights into the quality of additively manufactured parts and the processes that produce them.

computed tomography

microCT

quality

processes

additively manufactured


Input: A round robin test was conducted as follows: a series of standard test procedures (part sizes and shapes and test protocols) were applied–using one microCT system–to identical parts produced on a variety of metal additive manufacturing systems (specifically laser powder bed fusion systems).

round robin test

microCT

as

standard

protocols

metal additive manufacturing

laser powder bed fusion systems


Input: These are simple parts: a 10 mm cube, a 15 mm diameter vertical-built cylinder and a basic topology optimized example part–a bracket.

simple

mm

mm

cube

diameter

topology

bracket


Input: The 15 mm diameter cylinder acts as witness specimen for the build of the complex part.

mm

diameter

as

build


Input: All these were produced in Ti6Al4V, and in some cases parts were provided with variations in process parameters or manufacturing conditions which led to different types of intentional manufacturing flaws or defects.

variations

process parameters

flaws

defects

manufacturing

manufacturing

led


Input: The major result shown is that the analysis of a simple 10 mm cube clearly identifies incorrect process parameters even for very low levels of porosity, with unique porosity distributions and characteristics.

simple

mm

cube

process parameters

distributions

porosity

porosity


Input: The witness specimen (15 mm cylinder) allows clear identification of layered stop-start flaws, at a resolution better than a complex part built alongside it, allowing to identify defective builds.

mm

flaws

resolution

builds


Input: The results indicate a successful first step at standardized microCT analysis procedures for improvement of processes and quality control in additive manufacturing.

step

processes

quality control

microCT

additive manufacturing


Input: Understanding microstructural development in additive manufacturing under highly non-equilibrium cooling conditions and the consequent effects on mechanical properties of the final component is critical for accelerating industrial adoption of these manufacturing techniques.

microstructural

mechanical properties

additive manufacturing

cooling

manufacturing

component

industrial


Input: In this study, simple but effective theoretical solidification models are recalled to evaluate their ability to predict of microstructural features in additive manufacturing applications.

simple

additive manufacturing

theoretical solidification

microstructural


Input: As a case study, the resulting solidification microstructure selection maps are created to predict the stable growth modality and the columnar to equiaxed transition (CET) of an Al-10Si-0.5Mg alloy processed via Selective Laser Melting.

As

Al-10Si-0.5Mg alloy

case study

solidification microstructure

transition

Selective Laser Melting


Input: The potential of this method in microstructural predictions for additively manufactured products, as well as outstanding challenges and limitations, are discussed.

microstructural

additively manufactured products

as

as


Input: The present theoretical/experimental investigation deals with the problem of performing the static assessment of notched components made of additively manufactured Acrylonitrile Butadiene Styrene (ABS).

components

additively manufactured

Acrylonitrile Butadiene Styrene

ABS


Input: The notch strength of this 3D-printed material was investigated by testing a large number of specimens, with the experiments being run not only under tension, but also under three-point bending.

notch

testing

three-point bending


Input: The samples contained geometrical features of different sharpness and were manufactured (flat on the build plate) by changing the printing direction.

samples

manufactured

geometrical features

build plate


Input: Being supported by the experimental evidence, the hypothesis was formed that the mechanical response of 3D-printed ABS can be modelled effectively by treating it as a material that is linear-elastic, brittle, homogenous and isotropic.

experimental

mechanical response

be

as

material

brittle

isotropic


Input: This simplifying hypothesis allowed the Theory of Critical Distances to be employed also to assess static strength of 3D-printed ABS containing geometrical features.

be

strength

geometrical features


Input: The validation exercise based on the experimental results being generated demonstrates that this theory is highly accurate, with its use leading to predictions falling mainly within an error interval of about ±20%.

validation

experimental

predictions

error

accurate


Input: This level of accuracy is certainly satisfactory especially because this static assessment methodology can be used in situations of engineering relevance by making use of the results obtained by solving standard linear-elastic Finite Element models.

accuracy

methodology

standard

Finite Element models

be

engineering


Input: Material calibration was carried out for DMLS-MS1 and hybrid DMLS-MS1-H13.

Material

calibration


Input: Finite element modeling for Rockwell hardness test was implemented.

Finite element

Rockwell hardness test


Input: A combined FEM-analytical approach was developed to calculate fatigue life of DMLS-MS1.

fatigue life


Input: Finite element model of welding process on DMLS-MS1 was accomplished.

Finite element model

process

welding


Input: Fatigue life of welded DMLS-MS1 was calculated using the developed FE framework.

Fatigue life

welded

FE


Input: Additive manufacturing (AM) has been recently used to deposit metal powder on top of conventional metals.

Additive manufacturing

AM

metal powder

metals


Input: Of particular interest is hybrid additively manufactured steels which were found to be a suitable solution to benefit from features of each metal at different spots of a mechanical component.

additively manufactured steels

be

metal

solution

mechanical

component


Input: Due to its superior mechanical characteristics, maraging steel (MS1) has recently attracted tremendous attention for additive manufacturing applications mainly in aerospace, tool and die, and marine industries or to be 3D printed on top of other metals as a hybrid product using different techniques such as Direct Metal Laser Sintering (DMLS).

mechanical

aerospace

marine industries

maraging steel

be

metals

as

as

Metal

additive manufacturing

3D printed

Laser Sintering

DMLS

tool

die


Input: In this paper a predictive finite element (FE) model and a combined analytical-numerical framework were developed to evaluate the mechanical performance of hybrid additively manufactured components and facilitate the prediction of hardness and fatigue life of these parts.

finite element

model

framework

prediction

FE

mechanical

additively manufactured

hardness

fatigue life


Input: The proposed tools were employed in two scopes: First to simulate the indentation hardness test of hybrid DMLS-MS1-H13 steels; and second to calculate fatigue crack nucleation life of maraging steel including defects (i.e.

tools

indentation hardness test

steels

maraging steel

fatigue

nucleation

defects


Input: welding residual stresses).

welding

residual stresses


Input: Parameters such as local and global displacements, changes in Young’ s modulus, and hardness, high cycle fatigue life, welding temperature distribution, and residual stress were investigated.

Parameters

distribution

as

s

hardness

fatigue life

residual stress

welding

temperature


Input: The hardness experiments were carried out to improve the reported data found in similar studies, which were used as the main resource to validate the proposed numerical framework.

hardness

data

framework

as


Input: The capabilities of the presented frameworks enable this work to target existing ambiguities in additively manufactured mechanical components.

additively manufactured

components


Input: A net-shape synthesis process has been used to convert different isovolumetric precursor mixtures composed of either 100 vol% 86/14 molar Cr/Cr2O3 or 50 vol% 86/14 molar Cr/Cr2O3 with 50 vol% Cr3C2 to form multilayer chromium carbide materials suitable for reactive powder bed fusion additive manufacturing.

process

precursor

chromium carbide

powder bed fusion additive manufacturing


Input: Selective deposition was performed by patterning precursor layers using a masked high-volume, low-pressure slurry spray deposition technique.

deposition

deposition

precursor

slurry


Input: Following deposition, each layer was thermochemically converted to Cr3C2 at 950 °C in a gas atmosphere containing 76 vol.% Ar, 4 vol.% H2, 20% vol.% CH4.

deposition

gas

layer

Ar


Input: This process was repeated multiple times to construct layered structures representative of additively manufactured refractory ceramics.

process

layered structures

additively manufactured

ceramics


Input: X-ray diffraction characterization and quantitative phase analysis of each converted layer indicated that the average phase fraction of Cr3C2 present in the multi-layered samples following conversion from Cr/Cr2O3 and Cr3C2/Cr/Cr2O3 precursors was 94.5 wt% (SD = 0.92) and 98.8 wt% (SD = 0.21) respectively.

X-ray diffraction

quantitative phase

average

fraction

samples

layer


Input: Despite the higher phase fraction of Cr3C2 produced by the three-component precursor system, SEM imaging of the sample microstructures and fracture analysis indicated that increased bonding occurred in Cr3C2 produced by conversion of Cr/Cr2O3.

phase fraction

sample

fracture

bonding

precursor

microstructures

SEM

imaging


Input: This reaction-induced bonding enhanced the interlayer mechanical integrity.

bonding

mechanical integrity


Input: The results in this work demonstrate the use of isovolumetric reaction synthesis techniques that are broadly applicable for non-oxide ceramic production using reactive additive manufacturing methods.

non-oxide

ceramic

additive manufacturing


Input: A novel hydrodynamic cavitation abrasive finishing (HCAF) process was developed.

cavitation

process

abrasive


Input: Internal surface finishing was done using cavitation-aided microparticle abrasion.

surface finishing


Input: Synergistic effects enhanced the material removal and surface finish up to 80%.

material

surface finish


Input: Surface finishing additive-manufactured (AM) internal channels is challenging.

Surface finishing

AM


Input: In this study, a novel hydrodynamic cavitation abrasive finishing (HCAF) technique is proposed and its feasibility for surface finishing is analyzed.

cavitation

feasibility

abrasive

surface finishing


Input: Surface finishing is performed using controlled hydrodynamic cavitation erosion and microparticle abrasion phenomena.

Surface finishing

cavitation


Input: Various surface-finishing conditions were employed to investigate material removal and surface finish enhancement via synergistic effects in the HCAF process.

material

surface finish

process


Input: To quantify the contributions from each erosion mechanism, additively manufactured AlSi10Mg internal channels were surface finished in isolated conditions of a) liquid impingement, b) absolute cavitation erosion, c) absolute abrasion, and d) cavitation-assisted microparticle abrasion.

mechanism

surface

cavitation

additively manufactured

b

c


Input: The erosion rate and total thickness loss were established as the measurands to quantify the intensity of the surface finish.

as

surface finish


Input: A synergy map is proposed to quantify the contribution from the synergistic effects from hydrodynamic cavitation abrasive finishing.

cavitation

abrasive


Input: The synergistic material-removal mechanism is explained using surface morphology observations.

mechanism

surface morphology


Input: Hydrodynamic cavitation gradually removed loosely attached surface asperities in AM internal channels.

cavitation

surface asperities

AM


Input: The findings suggest that the synergistic effects in hydrodynamic cavitation abrasive finishing are effective in enhancing the material removal and surface-finish quality of AM components.

cavitation

quality

abrasive

material

AM


Input: Tracking codes are embedded inside 3D printed parts for product authentication.

3D printed parts


Input: Imaging method like micro-CT can retrieve the internal tracking code information.

Imaging

micro-CT


Input: Micro-CT images of the code present poor contrast and imaging artifact challenges.

Micro-CT

images

imaging


Input: Pre- and post-processing enable automatic and robust image reading and verification.

post-processing

image

verification


Input: The developed image processing methods have no dependence on the original image.

image

image


Input: The layer-by-layer printing process of additive manufacturing methods provides new opportunities to embed identification codes inside parts during manufacture.

layer-by-layer

process

manufacture

additive manufacturing


Input: The availability of reverse engineering tools has increased the risk of counterfeit part production and new authentication technologies such as the one proposed in this paper are required for many applications including aerospace components and medical implants and devices.

reverse engineering

technologies

production

as

aerospace components

medical implants


Input: The embedded codes are read by imaging techniques such as micro-Computed Tomography (micro-CT) scanners or radiography.

imaging

as

micro-CT

radiography


Input: The work presented in this paper is focused on developing methods that can improve the quality of the recovered micro-CT scanned code images such that they can be interpreted by standard code reader technology.

quality

images

standard

technology

micro-CT

be


Input: Inherent low contrast and the presence of imaging artifacts are the main challenges that need to be addressed.

imaging

be


Input: Image processing methods are developed to address these challenges using titanium and aluminum alloy specimens containing embedded quick response (QR) codes.

Image

titanium

aluminum alloy


Input: The proposed techniques for recovering the embedded codes are based on a combination of Mathematical Morphology and an innovative de-noising algorithm based on optimal image filtering techniques.

Mathematical

algorithm

image


Input: Additive manufacturing (AM), commonly referred to as 3D printing, was originally used for rapid prototyping.

Additive manufacturing

AM

3D printing

as

rapid prototyping


Input: However, research into new technologies has allowed AM to become applicable far beyond prototype fabrication.

research

technologies

prototype

AM

fabrication


Input: Oak Ridge National Laboratory (ORNL), sponsored by the Office of Naval Research, has designed and developed an anthropomorphic seven degree-of-freedom (DOF) dual arm hydraulic manipulator using metal AM technologies.

Laboratory

Research

designed

manipulator

metal AM


Input: The titanium manipulators are designed for subsea use.

titanium

manipulators

designed


Input: This article will detail the novel AM design of the hydraulic manipulator system.

AM

manipulator


Input: It will cover the manipulators’ pitch and rotary link designs, custom valves, hydraulic power unit, and the motivation for a dual arm design.

manipulators

designs

design

power


Input: In all manufacturing processes, there are several factors for which the final product exhibits dimensional and shape deviations from its ideal nominal geometry.

manufacturing processes

geometry


Input: In additive manufacturing (AM) and 3D printing, a part is built layerwise in a single manufacturing step and is often net-shaped.

additive manufacturing

AM

3D printing

manufacturing


Input: In most cases, no finishing operation is applied to change the dimensions of the product, apart from a reduction of the superficial roughness through sandblasting or polishing.

finishing operation

polishing

dimensions

reduction

roughness


Input: Therefore, knowing the dimensional tolerance of AM processes in advance is of fundamental importance, but little information is currently available in the literature.

dimensional tolerance

AM processes


Input: A benchmarking analysis of three different AM systems for polymers is presented in this paper.

AM

polymers


Input: The compared machines are based on different AM techniques which are fused filament fabrication (FFF), selective laser sintering (SLS) and Arburg plastic freeforming (APF).

machines

AM techniques

fused filament fabrication

FFF

selective laser sintering

SLS

plastic


Input: The dimensional accuracy of the machines has been defined using the ISO IT grades of a reference artifact.

dimensional accuracy

machines

ISO


Input: In the analysis of the benchmarking results, a specific focus is made on the importance of the thermal household in SLS and a parameter named SLS modulus is proposed to identify critical heat concentrations in the powder bed that may influence the dimensional accuracy of the manufactured part.

SLS

SLS

parameter

heat

manufactured

powder bed

dimensional accuracy


Input: Wire and arc additive manufacturing (WAAM), which is an additive manufacturing (AM) process that uses metal materials, has a higher fabricated volume per unit time but a lower fabricated shape accuracy compared with other methods.

Wire and arc additive manufacturing

WAAM

additive manufacturing

AM

process

fabricated

fabricated

metal materials

accuracy


Input: With this process, the surface roughness of fabricated objects is several hundred micrometers or more, and a finishing process is necessary.

process

fabricated

surface roughness

finishing process


Input: However, the fabricated objects after finishing can have uncut areas or can be overcut during the finishing process owing to the large difference between the target and actual fabricated shapes.

fabricated

fabricated

finishing

finishing process

areas

be


Input: Therefore, the objective of this study is to develop a cooperative system for WAAM and machining that includes a process that measures the shape of the fabricated object.

WAAM

machining

process

fabricated


Input: First, the three-dimensional (3-D) shape of the fabricated object was measured by structure from motion (SfM) and compared with the 3-D computer-aided design (CAD) data.

three-dimensional

fabricated

structure

data

design

CAD


Input: Second, the original design was modified, and the amount of material removed during finish cutting was optimized with the developed software.

design

material

cutting

software


Input: Finally, the fabricated hollow object was finished by milling to obtain a uniform wall thickness without any defects.

fabricated

defects

milling

wall thickness


Input: A 3-D fabricated object was measured by SfM, and it was observed that the measurement accuracy was sufficiently high for the requirements of the system.

measurement

accuracy


Input: In addition, a fabricated hollow quadrangular pyramid with a closed shape was machined with a computer numerical control (CNC) machine tool with the modification of the work origin.

fabricated

machined

computer numerical control

CNC

machine tool


Input: As a result, the amount of material removed during finish cutting was optimized, and the inclined wall thickness was uniform compared with that without modification.

As

material

cutting

wall thickness


Input: In addition, a hollow turbine blade with a freeform shape was successfully finished without any defects.

turbine blade

freeform

defects


Input: A wire arc additive manufactured sample with intentional defects is studied.

arc

defects

additive manufactured


Input: Owing to a lack of standards and codes, a calibration method was introduced.

standards

calibration


Input: The known size defects were used for calibration of the ultrasonic system.

defects

calibration


Input: In this study, Wire + Arc Additive Manufacture (WAAM) was employed to manufacture a steel specimen with intentionally embedded defects which were subsequently used for calibration of an ultrasonic phased array system and defect sizing.

Wire + Arc Additive Manufacture

WAAM

manufacture

defects

calibration

defect

steel


Input: An ABB robot was combined with the Cold Metal Transfer (CMT) Gas Metal Arc (GMA) process to deposit 20 layers of mild steel.

robot

Cold Metal Transfer

CMT

Gas Metal Arc

GMA

process

mild steel


Input: Tungsten-carbide balls (ø1-3 mm) were intentionally embedded inside the additive structure after the 4th, 8th, 12th and 18th layers to serve as ultrasonic reflectors, simulating defects within the WAAM sample.

mm

WAAM

additive

as

defects

sample


Input: An ultrasonic phased array system, consisting of a 5 MHz 64 Element phased array transducer, was used to inspect the WAAM sample non-destructively.

Element

transducer

WAAM

sample


Input: The majority of the reflectors were detected successfully using Total Focusing Method (TFM), proving that the tungsten carbide balls were successfully embedded during the WAAM process and also that these are good ultrasonic reflectors.

tungsten carbide balls

WAAM

process


Input: Owing to a lack of standards and codes for the ultrasonic inspection of WAAM samples (Lopez et al., 2018), a calibration method and step-by-step inspection strategy were introduced and then used to estimate the size and shape of an unknown lack of fusion (LoF) indication.

standards

samples

calibration

fusion

ultrasonic inspection

inspection

WAAM


Input: Corrosion behavior and biocompatibility of AM (SLM) and wrought 316 L SS are evaluated in physiological environment containing complexing agent i.e.

Corrosion behavior

biocompatibility

AM

SLM

wrought 316 L SS


Input: Ecorr for the SLM 316 L SS is consistently higher and breakdown potential, Ebd, is more than 3 times higher compared to the wrought.

SLM

316 L SS

wrought


Input: SLM sample exhibits wider passive region and higher charge transfer resistance (Rt) (approximately 1.5 to 2.5 times).

SLM

Rt

sample

resistance


Input: The SLM part shows better cell proliferation.

SLM

cell


Input: In order to mitigate potential implant failures, it is essential to determine the corrosion behavior of biomaterials in a realistic physiological environment.

implant

corrosion behavior

biomaterials


Input: In order to simulate the real oxidative nature of human body fluid, this research considers the effects of a complexing agent while determining the corrosion behavior of 316L stainless steel (SS) that has been fabricated by Selective Laser Melting (SLM) process.

fluid

316L stainless steel

SS

research

fabricated

process

corrosion behavior

Selective Laser Melting

SLM


Input: the citrate ion, in Phosphate Buffer Saline (PBS) solution strongly affects the passivation behavior of 316L SS by complex species formation.

ion

Buffer

solution

passivation

Phosphate

PBS

SS


Input: However, due to a rapid solidification process, the microstructural properties of the additively manufactured metal are not similar to that of the conventionally manufactured counterpart.

rapid solidification process

microstructural

manufactured

additively manufactured


Input: The microstructure of the SLM 316L SS contains refined sub-grains within each coarse grain and the formation of micro-inclusions i.e.

microstructure

grain

SLM

SS


Input: The SLM 316L SS had better pitting resistance and passive film stability.

SLM

SS

pitting

stability


Input: Ecorr for the SLM 316L SS was consistently higher and the breakdown potential, Ebd, was more than three times higher compared to the wrought counterpart as determined by cyclic potentiodynamic polarization.

SLM

SS

as

wrought

potentiodynamic polarization


Input: Moreover, the SLM sample had a wider passive region and higher charge transfer resistance (Rt) (approximately 1.5 to 2.5 times) as determined by cyclic voltammetry and electrochemical impedance spectroscopy, respectively.

SLM

Rt

sample

electrochemical

spectroscopy

resistance

as

cyclic voltammetry


Input: In addition, the attachment and proliferation tendency of MC3T3-E1 pre-osteoblast cells were studied to evaluate biocompatibility.

cells

biocompatibility


Input: The SLM part had better cell proliferation.

SLM

cell


Input: To summarize, in a physiological environment, the SLM 316L SS outperformed the conventional wrought 316L SS in terms of corrosion resistance and biocompatibility.

SLM

SS

SS

wrought

corrosion resistance

biocompatibility


Input: Wire arc additive manufacturing (WAAM) has become a promising metal 3D printing technology for fabricating large-scale and complex-shaped components.

Wire arc additive manufacturing

WAAM

fabricating

metal

3D printing technology

complex-shaped


Input: One major problem that limits the application of WAAM is the difficulty in controlling the dimensional accuracy under constantly changing interlayer temperatures.

limits

WAAM

dimensional accuracy

temperatures


Input: During the deposition process, as the wall height increases, the heat accumulates on the upper layers, which leads to the variation of the layer dimensions.

deposition process

as

heat

variation

layer

dimensions


Input: Normal practices such as introducing idle time and actively cooling the workpiece to mitigate such problems lack efficiency and practicality, respectively.

as

cooling

workpiece


Input: A novel process planning strategy is proposed in this paper and aims to achieve a continuous deposition process while ensuring dimensional accuracy.

process planning

deposition process

dimensional accuracy


Input: With the aid of a finite element model, the typical thermal transfer cycle of the workpiece was analyzed and then divided into different stages.

finite element model

workpiece


Input: When depositing material, the interlayer temperature of the subsequent layers can be predicted using the developed algorithm.

material

be

temperature

algorithm


Input: Hence, the process parameters (e.g., wire feed speed and travel speed) can be varied according to the predicted interlayer temperature using the developed adaptive process model, and this will ensure the uniform layer dimensions.

process parameters

predicted

process model

feed

temperature

layer

be

dimensions


Input: The result shows that such technique succeeds in a continuous fabrication of the component with high accuracy and efficiency.

fabrication

component

accuracy


Input: 2219-Al specimens with no cracks and less pores were fabricated by novel laser-TIG hybrid additive manufacturing.

pores

fabricated

additive manufacturing


Input: The mechanical properties were higher than that fabricated by conventional TIG, CMT or SLM.

mechanical properties

fabricated

TIG

CMT

SLM


Input: The presence of laser could refine grains and improve the uniformity of elements and eutectics.

laser

grains

elements


Input: Owing to its high strength to weight ratio, Al–Cu alloy is extensively used in the aeronautic and aerospace industries.

strength to weight ratio

alloy

aerospace industries


Input: However, there are some shortcomings in the additive manufacturing of Al–Cu alloy, such as cracks and poor strength.

additive manufacturing

alloy

as

strength


Input: In this work, Al–Cu (2219-Al) specimens with excellent mechanical properties were fabricated by laser-Tungsten Inert Gas (TIG) hybrid additive manufacturing.

mechanical properties

fabricated

Inert Gas

TIG

additive manufacturing


Input: From the microstructural studies, the average grain size in the laser zone (LZ) decreased to 14.4 μm, which was approximately 40.3% smaller than that in the arc zone (AZ).

microstructural

average

arc

laser


Input: Its crystal orientation relationship was described as [110] α∥ [002] θ, (110) α∥ (002) θ between the α-Al matrix and the θ phase.

crystal orientation

as

phase


Input: Meanwhile, the θ′ phase characterized a good coherent relationship with the α-Al matrix, which resulted in low phase boundary energy.

phase

phase boundary


Input: Furthermore, the deposited specimens exhibited a yield strength of 155.5 ± 7.9 MPa and an ultimate tensile strength of 301.5 ± 16.7 MPa, with an elongation of 12.8 ± 2.8%.

yield strength

ultimate tensile strength

elongation

MPa

MPa


Input: These mechanical properties were higher than in specimens fabricated by TIG, CMT and SLM methods.

mechanical properties

fabricated

TIG

CMT

SLM


Input: The improved properties were predominately related to the smaller size of eutectics, the uniform distribution of Cu and the semi-coherent θ′ phases in the LZ.

properties

distribution

Cu


Input: The combined effect of laser and arc can yield components with excellent mechanical properties, promoting the material for an expansive range of applications.

laser

arc

mechanical properties

components

material

range


Input: New microstructural features were found in the TiAl alloy manufactured using the gas tungsten arc welding-based additive manufacturing technology.

microstructural

gas

arc

alloy

additive manufacturing


Input: The ion-irradiation responses of the new microstructure features were investigated in-situ via irradiation with 1 MeV Kr2+ ions at room and 873 K. Examination of the microstructure showed that the typical lamellar microstructure consisting of α2-Ti3Al and γ-TiAl phases formed α2/γ lamellar interfaces and γ/γ twin boundaries.

microstructure

in-situ

microstructure

lamellar

lamellar

irradiation

boundaries


Input: Apart from this, the γ lamellae were also found to form γ/γ lamellar boundaries with the two γ lamellae in the same orientation or the < 10-1 > // < 411 > orientation relationship.

lamellae

lamellae

lamellar

orientation

orientation

boundaries


Input: This is not observed in the TiAl alloys fabricated using traditional alloy fabrication methods.

alloys

alloy


Input: Kr ion-irradiation at room and elevated temperatures resulted in no significant difference in the morphologies of most radiation-induced defects in the < 411 > orientated γ lamellae and the < 10-1 > orientated γ lamellae.

temperatures

morphologies

defects

lamellae

lamellae


Input: However, the areas of the new boundaries exhibited different damage morphologies in comparison with the traditional γ/γ twin boundaries.

areas

boundaries

boundaries

damage


Input: The formation mechanisms of the new microstructural features formed in the additive manufacturing process and their irradiation behaviour are investigated and discussed.

microstructural

additive manufacturing process

irradiation


Input: Additive manufacturing can produce parts with complex geometries in fewer steps than conventional processing, which leads to cost reduction and a higher quality of goods.

Additive manufacturing

complex geometries

cost reduction

quality


Input: One potential application is the production of molds and dies with conformal cooling for injection molding, die casting, and forging.

production

injection molding

die casting

forging

molds

dies

conformal cooling


Input: AISI H13 tool steel is typically used in these applications because of its high hardness at elevated temperatures, high wear resistance, and good toughness.

H13 tool steel

hardness

wear resistance

toughness

temperatures


Input: However, available data on the processing of H13 steel by additive manufacturing are still scarce.

data

H13 steel

additive manufacturing


Input: Thus, this study focused on the processability of H13 tool steel by powder bed fusion and its microstructural characterization.

H13 tool steel

powder bed fusion

microstructural characterization


Input: Laser power (97−216 W) and scan speed (300−700 mm/s) were varied, and the consolidation of parts, common defects, solidification structure, microstructure, and hardness were evaluated.

Laser power

scan speed

consolidation

defects

solidification

microstructure

hardness


Input: Over the range of processing parameters, microstructural features were mostly identical, consisting of a predominantly cellular solidification structure of martensite and 19.8% –25.9% of retained austenite.

range

parameters

microstructural

solidification

martensite

retained austenite


Input: Cellular/dendritic solidification structure displayed C, Cr, and V segregation toward cell walls.

solidification

segregation

C

Cr

V

cell


Input: The thermal cycle resulted in alternating layers of heat-affected zones, which varied somewhat in hardness and microstructure.

thermal cycle

hardness

microstructure


Input: Retained austenite was correlated to the solidification structure and displayed a preferential orientation with {001} //build direction.

Retained austenite

correlated

solidification

orientation


Input: Density and porosity maps were obtained by helium gas pycnometry and light optical microscopy, respectively, and, along with linear crack density, were used to determine appropriate processing parameters for H13 tool steel.

Density and porosity

helium

H13 tool steel

gas

parameters

optical microscopy

density


Input: Thermal diffusivity, thermal conductivity, and thermal capacity were measured to determine dimensionless processing parameters, which were then compared to others reported in the literature.

Thermal diffusivity

capacity

parameters

thermal conductivity


Input: The complex, nonequilibrium physical, chemical, and metallurgical nature of additive manufacturing (AM) tends to lead to uncontrollable and unpredictable material and structural properties.

metallurgical

additive manufacturing

AM

lead

material

properties


Input: In this study, we investigated a laser opto-ultrasonic dual (LOUD) detection approach for simultaneous and real-time detection of elemental compositions, structural defects, and residual stress in aluminium (Al) alloy components during wire + arc additive manufacturing (WAAM) processes.

laser

structural defects

processes

residual stress

aluminium

Al

alloy

wire + arc additive manufacturing

WAAM


Input: In this approach, a pulsed-laser beam was used to excite the surfaces of Al alloy samples to generate ultrasound and optical spectra.

beam

surfaces

Al alloy

optical spectra


Input: As a result, the compositional information can be obtained from the optical spectra, while the structural defects and residual stress distributions can be extracted from the ultrasonic signals.

As

be

be

optical spectra

structural defects

distributions

residual stress


Input: The silicon (Si) and copper (Cu) compositions obtained from optical spectral analyses are consistent with those obtained from the electron-probe microanalyses (EPMA).

silicon

Si

copper

Cu

optical

EPMA


Input: The 1 mm blowhole and the residual stress distribution of the sample were detected by the ultrasonic signals in the LOUD detection, which shows consistency with the conventional ultrasonic testing (UT).

mm

blowhole

distribution

sample

consistency

residual stress

UT

testing


Input: Both results indicate that the LOUD detection holds the promising of becoming an effective testing method for AM processes to ensure quality control and process feedback.

testing

AM processes

quality control

process

feedback


Input: Wire + Arc Additive Manufacturing (WAAM) has already proven to be successful for the production of large metal parts.

Wire + Arc Additive Manufacturing

WAAM

production

be

metal


Input: However, there are still no specific standards available to label the quality requirements of the parts produced by WAAM and this is preventing a more widespread adoption of the technique.A crucial step towards the quality assurance of WAAM parts will be the development of Non-Destructive Testing (NDT) systems capable of identifying defects while parts are being produced.

standards

quality

step

quality

NDT

defects

WAAM

WAAM

be

Non-Destructive Testing


Input: In this regard, Eddy Current Testing (ECT) can play a significant role, by allowing the inspection of both ferromagnetic and non-ferromagnetic materials, with high speeds and without contact with the material surface.

Eddy Current Testing

inspection

materials

contact

material


Input: The limitation here is that commercial ECT targets only the inspection of surface and subsurface defects.This study is focused on the development of a NDT system which includes customized ECT probes for the inline layer-by-layer detection of defects in aluminium WAAM samples.

inspection

surface

NDT

layer-by-layer

defects

samples

probes

aluminium


Input: Results revealed that the developed EC probes were able to locate artificial defects: at depths up to 5 mm; with a thickness as small as 350 μm; with the probe up to 5 mm away from the inspected sample surface.The developed ECT probes proved to surpass the limitation of commercial ones.

probes

probe

probes

defects

sample

mm

mm

as

as


Input: Also, these probes were able to overcome the limitations caused by the surface roughness of the samples and the high temperatures involved in the deposition process.

probes

surface roughness

samples

temperatures

deposition process


Input: These preliminary results represent an important step for the development of NDT systems for WAAM.

step

NDT

WAAM


Input: By using filaments comprising metal or ceramic powders and polymer binders, solid metal and ceramic parts can be created by combining low-cost fused filament fabrication (FFF) with debinding and sintering.

filaments

metal

ceramic powders

polymer binders

metal

ceramic

be

fused filament fabrication

FFF

sintering

debinding


Input: In this work, we explored a fabrication route using a FFF filament filled with 316 L steel powder at 55 vol.-%.

fabrication

FFF

steel powder


Input: We investigated the printing, debinding and sintering parameters and optimized them with respect to the mechanical properties of the final part.

debinding

parameters

mechanical properties

sintering


Input: Special focus was placed on debinding and sintering in order to obtain components of low residual porosity.

debinding

residual

sintering

components

porosity


Input: Solvent debinding of the printed green bodies created an internal network of interconnected pores and was followed by thermal debinding.

debinding

green bodies

pores

thermal debinding


Input: Thermal debinding allowed for complete removal of the remaining binder and produced mechanically stable brown parts.

Thermal debinding

brown parts

binder


Input: Sintering at 1360 °C provided densification of the parts and generated nearly isotropic linear shrinkage of about 20%.

Sintering

densification

isotropic

shrinkage


Input: Using optimized parameters, it was possible to fabricate 316 L steel components with a density greater than 95% via the material extrusion additive manufacturing, debinding and sintering route, with achievable deflections in a 3-point bending test similar to rolled sheet material, albeit at lower strength.

parameters

debinding

fabricate

material extrusion additive manufacturing

sintering

steel

sheet material

components

density

strength

bending test


Input: Fabricating a magnesium alloy using wire-and-arc-based additive manufacturing was successfully conducted.

Fabricating

additive manufacturing

magnesium alloy


Input: Suitable processing conditions for realizing a solid structure with few weld defects were clarified.

structure

defects

weld


Input: Fabricated object has sufficient tensile strength compared with the bulk material.

Fabricated

tensile strength

material


Input: Microstructure at the boundary between the substrate and the fabricated object is finer than that on the top layer.

Microstructure

fabricated

boundary

substrate

layer


Input: Material properties, such as porosity, tensile strength, and microstructure, of magnesium-alloy components fabricated using wire-and-arc-based additive-manufacturing techniques, which essentially represent a form of arc-welding technology have been examined.

Material properties

microstructure

technology

as

tensile strength

components


Input: In the proposed method, the wire material is melted by arc discharge, and the molten metal is subsequently solidified and accumulated.

material

molten metal

melted

arc


Input: Magnesium wire developed in this study facilitated fabrication of magnesium-alloy components using the said additive-manufacturing process.

Magnesium

fabrication

components

process


Input: Subsequently, combinations of fabrication conditions, such as the welding current, torch feed speed, and cross feed of the torch, were explored, and suitable conditions for realizing a solid structure with fewer weld defects compared to those observed when using die-casting and other manufacturing methods, were determined.

fabrication

welding

manufacturing

as

feed

feed

structure

defects

weld


Input: Tensile tests and microstructure observations were also performed to elucidate mechanical properties of magnesium alloy components fabricated via the said wire-and-arc-based technique.

Tensile tests

microstructure

mechanical properties

magnesium alloy

components


Input: It was demonstrated that the fabricated object possesses sufficient tensile strength compared to the observed standard value of the bulk material.

fabricated

standard

tensile strength

material


Input: Furthermore, results from microstructure observations demonstrated that the higher the torch feed speed, the finer is the microstructure.

microstructure

microstructure

feed


Input: Moreover, the observed microstructure at the boundary between the substrate and fabricated object was finer compared to that at the top layer.

microstructure

fabricated

boundary

substrate

layer


Input: WAAM (Wire Arc Additive Manufacturing) is a metal AM (Additive Manufacturing) technology that allows high deposition rates and the manufacturability of very large components, compared to other AM technologies.

WAAM

Wire Arc Additive Manufacturing

metal AM

Additive Manufacturing

AM technologies

technology

manufacturability

high deposition rates

components


Input: Distortions and residual stresses affecting the manufactured parts represent the main drawbacks of this AM technique.

residual stresses

manufactured

AM technique


Input: FE (Finite Element) modeling could represent an effective tool to tackle such issues, since it can be used to optimize process parameters, deposition paths and to test alternative mitigation strategies.

FE

be

Finite Element

process parameters

modeling

tool

deposition paths


Input: Nevertheless, specific modeling strategies are needed to reduce the computational cost of the process simulation, such as reducing the number of elements used in discretizing the model.

modeling

process simulation

as

elements

model


Input: The proposed technique is based on dividing the substrate in several zones, separately discretized and then connected by means of a double sided contact algorithm.

substrate

contact

algorithm


Input: This strategy allows to achieve a significant reduction of the number of elements required, without affecting their quality parameters.

reduction

quality parameters

elements


Input: The geometry and dimension of the mesh zones are identified through a dedicated algorithm that allows to achieve an accurate temperature prediction with the minimum element number.

geometry

algorithm

prediction

dimension

accurate

element


Input: The effectiveness of the proposed technique was tested by means of both numerical and experimental validation tests.

effectiveness

experimental


Input: AlCoFeNiSmTiV based new high entropy alloys were designed and fabricated using additive manufacturing technique.

alloys

designed

fabricated

additive manufacturing


Input: Elevated temperature corrosion performance of these alloys were studied.

temperature

corrosion

alloys


Input: Phase analysis results indicated the presence of a single FCC phase in these HEAs after enduring corrosive atmospheres.

Phase

FCC

corrosive


Input: High entropy alloys have attracted great interest due to their great stability and exceptional mechanical properties.

alloys

stability

mechanical properties


Input: Due to growing demand of novel engineering materials, which can endure harsh corrosive atmospheres, HEAs have been studied extensively to meet the demands of challenging industrial environments.

engineering materials

corrosive

industrial


Input: Current manufacturing techniques of HEAs include arc-melting or spark plasma sintering, which are limited by factors such as high energy, grain refinement, alloying, and size limitations.

manufacturing

spark plasma sintering

as

grain refinement

alloying


Input: In this study we report elevated temperature corrosion behavior of two new HEAs AlCoFeNiTiV0.9Sm0.1 and AlCoFeNiV0.9Sm0.1, produced by laser-based additive manufacturing, which offers high freedom of design, fast prototyping, and rapid quenching rates that are ideal for many industrial applications.

temperature

corrosion behavior

laser-based additive manufacturing

quenching

design

prototyping

industrial


Input: These alloys were tested in corrosive syngas atmosphere at elevated temperatures to explore their applicability in such harsh environments.

alloys

corrosive

temperatures


Input: Phase analysis results indicated the presence of a single FCC phase in these HEAs with no major surface cracks after enduring such corrosive atmospheres.

Phase

FCC

surface

corrosive


Input: These alloys exhibited good corrosion resistance as revealed by electrochemical testing methods.

alloys

as

corrosion resistance

electrochemical


Input: CALPHAD and DFT simulations were also performed to reveal the phase stability and crystal structures to further corroborate our experimental results.

DFT

phase

experimental

crystal structures


Input: Wire and arc additive manufacturing (WAAM) is an additive manufacturing (AM) technology that uses wire-form materials and arc discharges as the energy source.

Wire and arc additive manufacturing

WAAM

additive manufacturing

AM

technology

materials

arc

as

source


Input: AM techniques can fabricate complicated shapes that can not be obtained via conventional processing.

AM techniques

fabricate

be


Input: Building lattice structures inside components enables weight reduction while maintaining high strength.

lattice structures

components

weight

reduction

strength


Input: Strut shapes must be constructed to form these lattice structures using WAAM.

Strut

be

lattice structures

WAAM


Input: For fabricating strut shapes with high accuracy, the process parameters should be optimized.

fabricating

accuracy

process parameters

be


Input: However, the relationship between layer geometry and process parameters is not clear.

layer

geometry

process parameters


Input: Therefore, in this study, struts were fabricated under various process conditions to investigate the influences of process parameters on the built object geometry.

struts

fabricated

process

process parameters

geometry


Input: The results showed that fabrication of strut shapes depends on the heat input condition.

fabrication

strut

heat


Input: Moreover, it was found that the arc discharge time had the highest influence on the layer height and diameter.

arc

diameter

layer height


Input: The inclination angle of an overhanging shape had little influence on the dimensional accuracy of the built object.

inclination angle

dimensional accuracy


Input: In addition, computer-aided manufacturing (CAM) system was developed for the fabrication of lattice structures, and the lattice structures were successfully built using WAAM.

computer-aided manufacturing

CAM

fabrication

WAAM

lattice structures

lattice structures


Input: The build accuracy was measured using an x-ray computed tomography (CT) scanner; the deviation in the structures designed using the CAM system and the actual fabricated structures measured using the CT scanner was lower than approximately ±2.3 mm.

build

accuracy

x-ray computed tomography

CT

CAM

CT

designed

fabricated

mm


Input: The integration of coaxial connectors into the filter and waveguide designs via 3D printing eliminates the need for two additional bulky external SMA-to-waveguide transitions, and allows for customizable integrated SMA-to-waveguide transitions that minimize impedance mismatch.

filter

designs

3D printing


Input: Four designs, including air-filled and polycarbonate (PC) dielectric-filled waveguides and two-pole filters, are modeled and manufactured using additive manufacturing to demonstrate this integrative approach.

designs

polycarbonate

PC

filters

manufactured

additive manufacturing


Input: PC dielectric posts are also incorporated into the device to provide additional reinforcement to the coaxial connectors without impacting the radio frequency (RF) performance.

PC

dielectric

reinforcement

radio frequency

performance


Input: This paper discusses the topology optimization and additive manufacturing (AM) specific re-design of a metallic C-frame as it is used in the riveting process in the automotive industry.

topology optimization

additive manufacturing

AM

metallic

as

process

automotive industry


Input: The main objective of the optimization and re-design process is the reduction of the structural weight where special attention needs to be paid to the specific manufacturing process of powder bed fusion which is a powder based layerwise additive manufacturing process.

optimization

process

reduction

weight

be

powder

manufacturing process

powder bed fusion

additive manufacturing process


Input: The initial optimization and AM specific re-design are performed under consideration of a number of free parameters that drive the performance and weight of the C-frame, and several generated solutions are compared under special consideration of the weight, the mechanical performance and the general manufacturability using powder bed fusion.

optimization

parameters

performance

manufacturability

AM

powder bed fusion

weight

weight

mechanical


Input: The selected optimized solution then undergoes a final detailed re-design which focusses on given manufacturing restrictions.

solution

manufacturing


Input: The mechanical performance of the optimized C-frame is assessed employing detailed finite element simulations by evaluating the stress and deformation state.

mechanical

finite element

deformation

stress


Input: The general manufacturability of the optimized part by powder bed fusion is demonstrated by the manufacturing of a scaled prototype.

manufacturability

prototype

powder bed fusion

manufacturing


Input: In order to enable a comparison of the new AM solution with a classical manufacturing process, an optimized C-frame geared towards classical milling is established as well.

AM

manufacturing process

milling

as


Input: Both solutions are compared concerning weight, mechanical performance, manufacturability and economic aspects, and it can be shown that the AM solution offers a number of advantages that can not be exploited when employing classical means of manufacturing.

weight

mechanical

manufacturability

be

be

AM

manufacturing


Input: This paper may serve as an introduction to the rather complex field of AM design of load bearing structures and is an illustrated case study thereof which can be of use for engineers working in this specific field that is still the topic of global academic and industrial research.

as

be

AM

case study

industrial


Input: Multifunctional lattice materials exhibit functionalities beyond conventional load-bearing usage and are usually fabricated by additive manufacturing.

lattice

fabricated

load-bearing

additive manufacturing


Input: This work introduces a new class of functional lattice materials called liquid metal lattice materials.

lattice

lattice

liquid metal


Input: These lattice materials consist of liquid metals and elastomers organized in a core-shell manner.

lattice

liquid metals

elastomers


Input: This hybrid design induces a shape memory effect by harnessing the solid-liquid phase transition of liquid metals.

design

shape memory effect

phase

liquid metals


Input: Consequently, several remarkable functionalities are achieved such as recoverable energy absorption, tunable rigidity, and reconfigurable behaviors.

as

energy absorption


Input: These liquid metal lattice materials are fabricated by using a hybrid manufacturing approach, which integrates the 3D printing, vacuum casting, and conformal coating techniques.

liquid metal

lattice

fabricated

hybrid manufacturing

3D printing

vacuum casting

coating


Input: A variety of lattice structures are presented to demonstrate the capability of this hybrid manufacturing method and the functionalities of liquid metal lattice materials.

lattice structures

hybrid manufacturing

lattice

liquid metal


Input: This new class of lattice materials have promising applications in aerospace, robotics, tunable metamaterials, etc.

lattice

aerospace

robotics

metamaterials


Input: Additive manufacturing (AM) of tungsten carbide-cobalt (WC-Co) is explored starting with WC preforms shaped with binder jet additive manufacturing (BJAM) followed by melt infiltration of Co.

Additive manufacturing

AM

additive manufacturing

tungsten

WC

binder

Co

melt infiltration


Input: The research objective is to demonstrate the ability to net-shape WC-Co composites through BJAM of a WC preform followed by backfilling with cobalt via pressureless infiltration.

research

infiltration

composites

WC

cobalt


Input: This method also has the potential to minimize shrinkage and grain growth compared to other AM techniques.

shrinkage

grain growth

AM techniques


Input: The effects of sintering, Co content, and infiltration time on the net shaping and properties of processed composites are shown.

sintering

shaping

Co

composites

infiltration

properties

processed


Input: The best shaped material had an average grain size of 5.1 μm, 32 vol.% Co, density of 98.54% theoretical, fracture toughness of 23.2 MPa m1/2, and hardness of 9.0 GPa.

material

Co

average

theoretical

fracture

MPa

density

hardness

GPa


Input: Data presented illustrates that the proposed approach results in favorable ceramic-metal (cermet) properties and is viable for fabricating cermets of other material combinations.

Data

properties

ceramic-metal

cermet

cermets

material

fabricating


Input: Successful AM of cermets provides complex geometries, high throughout, and low costs.

AM

cermets

complex geometries


Input: Online nondestructive testing for quality control is a critical direction for research in additive manufacturing in the future.

nondestructive testing

quality control

research

additive manufacturing


Input: In this study, for the first time, optical emission spectroscopy was employed to probe the arc characteristics in the wire arc additive manufacturing (WAAM) of an Al alloy and to detect its structural features.

optical

emission

probe

arc

wire arc additive manufacturing

WAAM

Al alloy


Input: The arc characteristics, such as spectral intensity, electron density, and electron temperature, were calculated based on the atomic emission spectral lines.

arc

as

density

temperature

emission


Input: The resulting structural features of the deposited layers, namely the forming width, composition, grain size, and porosity defects, were analyzed, and a correlation between the arc characteristics and the structural features was proposed.

deposited layers

forming

composition

defects

arc

grain size

porosity


Input: The arc cathode size, which changed with the number of deposited layers, controlled the arc energy distribution.

arc

arc

distribution

deposited layers


Input: Hence, the forming width had an approximately linear relation with the spectral intensity of Mg (a constituent of the alloy used for the wire feed) and the electron density.

forming

Mg

alloy

feed

density


Input: The porosity in the alloy was observed to be caused by H, which was a dominant pollutant in the process.

porosity

alloy

be

process


Input: Furthermore, the correlation between the porosity and H spectral intensity was observed to be approximately linear.

porosity

be


Input: However, no significant correlation between the grain size and the spectrum was noticeable.

grain size


Input: The results from this study establish the applicability of spectral diagnosis of the forming size and the porosity in WAAM.

forming

WAAM

porosity


Input: Specification and analysis of the system structure and components of a desktop additive manufacturing (AM) system.

Specification

structure

components

additive manufacturing

AM


Input: Physical modeling of the energy consumption behavior of the desktop AM system using function-oriented bond graph.

modeling

AM


Input: Development of an energy simulation tool for the desktop AM system using MATLAB®/Simulink® platform.

simulation

AM

platform


Input: Experimental validation of the simulation accuracy of the developed simulation approach.

Experimental

simulation accuracy

simulation


Input: The assessment and minimization of energy consumptions of additive manufacturing (AM) processes are currently emerging research tasks.

additive manufacturing

AM

processes

research


Input: It is evident that the energy consumption of an AM process can be one or two orders of magnitude higher than conventional manufacturing processes.

AM process

conventional manufacturing

be

magnitude


Input: For improving the sustainability performance of AM, the energy use of AM should be evaluated and optimized in the design phase for planning products and AM processes.

sustainability performance

AM

AM

planning

AM processes

be

design


Input: In order to support the quantification and evaluation of the energy consumption of AM, we have developed an energy simulation of a desktop AM system by using a physical modeling approach.

support

AM

AM

simulation

modeling


Input: Moreover, experiments have been carried out to validate and confirm the simulation accuracy and reliability.

simulation accuracy

reliability


Input: The result of the experimental validation has shown that the accuracy of the developed simulation approach can be up to approximately 98%.

experimental

accuracy

simulation

be


Input: Metal additive manufacturing is moving from rapid prototyping to on-demand manufacturing and even to serial production.

Metal additive manufacturing

manufacturing

production

rapid prototyping


Input: Consistent part quality and development of a wider range of available materials are key for wider adoption.

quality

materials

range


Input: This requires control and optimization of various laser and scanning parameters.

optimization

scanning parameters

laser


Input: Therefore, process modeling has been extensively pursued to reduce experimental runs in the search for parameters that produce dense, high-quality parts for the given alloy.

process modeling

experimental

parameters

alloy


Input: However, these optimal parameters remain machine-specific if conditions defined by the machine architecture are not considered.

parameters

machine

architecture


Input: Previous studies have shown that shielding gas flow is one such parameter that affects porosity and mechanical properties of parts produced with laser powder bed fusion.

gas

parameter

mechanical properties

porosity

laser powder bed fusion


Input: In this study, the effect of shielding gas flow velocity on porosity and melt pool geometry in laser powder bed fusion additive manufacturing is studied.

gas

geometry

porosity

melt pool

laser powder bed fusion additive manufacturing


Input: As the vapor plume, and how effectively it is removed by the shielding gas flow, have a significant effect on the melt pool geometry in laser powder bed fusion, models aiming at predicting the melt pool geometry and attempts to transfer process parameters from one machine to another should consider the effect of the shielding gas flow.

As

melt pool

melt pool

gas

geometry

geometry

process parameters

gas

laser powder bed fusion

machine


Input: Nickel Aluminum Bronze square bars were printed via wire-arc additive manufacturing.

Nickel Aluminum Bronze

wire-arc additive manufacturing


Input: Formation of various κ-phases were discussed and compared with cast alloy.

cast

alloy


Input: Additive Manufactured (AM) alloy has fine solidification structure.

Additive Manufactured

AM

alloy

solidification


Input: AM-NAB exhibited superior tensile properties than the cast-NAB.

tensile properties


Input: As a step forward toward the development of the next generation of nickel aluminum bronze (NAB) components using wire-arc additive manufacturing (WAAM), square bars were printed in the vertical direction.

As

nickel aluminum bronze

NAB

step

vertical

components

wire-arc additive manufacturing

WAAM


Input: The as-built microstructure was characterized using multi-scale electron microscopy techniques, where the differences in phase formation were compared to the reference cast-NAB based on the solidification characteristics.

microstructure

phase

solidification

electron microscopy


Input: The as-cast microstructure typically consists of Cu-rich α-matrix, and four types of intermetallic particles referred to as κ-phases.

microstructure

intermetallic

as


Input: In the WAAM-NAB, the formation of κI was suppressed due to high cooling rates.

cooling rates


Input: The microstructure was finer and the volume fraction of intermetallic particles was significantly lower than that of the cast-NAB.

microstructure

volume fraction

intermetallic


Input: Based on energy dispersive spectroscopy (EDS) technique and diffraction pattern analysis using transmission electron microscopy (TEM), the phases formed in the interdendritic regions were identified as κII (globular Fe3Al) and κIII (lamellar NiAl), whereas numerous fine (5–10 nm) Fe-rich κIV particles were precipitated uniformly within the α-matrix.

energy dispersive spectroscopy

EDS

diffraction pattern

transmission electron microscopy

TEM

as

lamellar

particles


Input: Electron backscatter diffraction analysis revealed weak texture on both parallel and perpendicular planes to the building direction with (100) poles rotated away from the build direction.

Electron backscatter diffraction

texture

building direction

build direction


Input: The WAAM-NAB sample exhibited considerably higher yield strength (˜88 MPa) and elongation (˜10%) than the cast-NAB, but the gain in the ultimate tensile strength was marginal.

sample

MPa

yield strength

elongation

ultimate tensile strength

gain


Input: Processing of Inconel 718 and copper alloy GRCop-84 as a bimetallic structure using laser engineered net shaping (LENS).

Inconel 718

copper alloy

as

structure

laser engineered net shaping

LENS


Input: A compositionally gradient layer with high laser energy input helped to process these bimetallic structures.

layer

laser energy

process


Input: The bimetallic structure resulted in high thermal diffusivity as compared to pure Inconel 718.

structure

thermal diffusivity

as

Inconel 718


Input: Deposition of GRCop-84 Increased the thermal diffusivity of Inconel 718 by ∼250%.

Deposition

thermal diffusivity

Inconel 718


Input: To understand processing ability and measure resultant interfacial and thermal properties of Inconel 718 and copper alloy GRCop-84, bimetallic structures were fabricated using laser engineering net shaping (LENS™), a commercially available additive manufacturing technique.

thermal properties

fabricated

Inconel 718

copper alloy

laser

engineering

shaping

additive manufacturing


Input: It was hypothesized that additively combining the two aerospace alloys would form a unique bimetallic structure with improved thermophysical properties compared to the Inconel 718 alloy.

aerospace

structure

properties

Inconel 718 alloy


Input: Two approaches were used: the direct deposition of GRCop-84 on Inconel 718 and the compositional gradation of the two alloys.

deposition

Inconel 718

alloys


Input: Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray Diffraction (XRD), Vickers microhardness and flash thermal diffusivity were used to characterize these bimetallic structures to validate our hypothesis.

Scanning electron microscopy

SEM

energy dispersive spectroscopy

EDS

X-ray Diffraction

XRD

diffusivity

microhardness

flash


Input: The compositional gradation approach showed a gradual transition of Inconel 718 and GRCop-84 elements at the interface, which was also reflected in the cross-sectional hardness profile across the bimetallic interface.

transition

interface

interface

Inconel 718

elements

hardness


Input: SEM images showed columnar grain structures at the interfaces with Cr2Nb precipitate accumulation along grain boundaries and the substrate-deposit interface.

SEM

images

grain boundaries

interface

columnar grain

precipitate


Input: The average thermal diffusivity of the bimetallic structure was measured at 11.33 mm2/s for the temperature range of 50 °C–300 °C; a 250% increase in diffusivity when compared to the pure Inconel 718 alloy at 3.20 mm2/s.

average

structure

diffusivity

diffusivity

temperature range

Inconel 718 alloy


Input: Conductivity of the bimetallic structures increased by almost 300% compared to Inconel 718 as well.

Conductivity

Inconel 718

as


Input: Such structures with designed compositional gradation and tailored thermal properties opens up the possibilities of multi-material metal additive manufacturing for next generation of aerospace structures.

designed

thermal properties

multi-material

metal additive manufacturing

aerospace


Input: Depth-sensing (instrumented) indentation testing technique is a robust, reliable, convenient and non-destructive characterization method to study small-scale mechanical properties and rate-dependent plastic deformation in metals and alloys at ambient and elevated temperatures.

indentation

mechanical properties

plastic deformation

metals

alloys

temperatures


Input: In the present paper, depth-sensing indentation creep behavior of an additively manufactured, via laser powder bed fusion (L-PBF) method, Ti-6Al-4V alloy is studied at ambient temperature.

indentation

creep behavior

additively manufactured

laser powder bed fusion

L-PBF

Ti-6Al-4V alloy

temperature


Input: Indentation creep tests were performed through a dual-stage scheme (loading followed by a constant load-holding and unloading) at different peak loads of 250 mN, 350 mN, and 450 mN with holding time of 400 s. Creep parameters including creep rate, creep stress exponent, and indentation size effect were analyzed, according to the Oliver and Pharr method, at different additive manufacturing scan directions and scan sizes.

Indentation

indentation

creep tests

mN

mN

mN

Creep

creep

creep

additive manufacturing


Input: To assess processing parameter/ microstructure/ creep property correlations in the additively manufacture Ti-6Al-4V alloy, microstructural quantitative analyses (i.e.

creep

additively manufacture

alloy

microstructural


Input: optical microscopy and scanning electron microscopy) were performed as well.

optical microscopy

scanning electron microscopy

as


Input: The findings of this study, according to stress exponent values, showed that the controlling mechanism of the creep at ambient temperature for the examined L-PBF Ti-6Al-4V is mainly glide-controlled dislocation creep.

stress

creep

creep

mechanism

dislocation

temperature

L-PBF


Input: These findings were compared against traditionally processed Ti-6Al-4V as well.

processed

as


Input: Additively manufactured, short fiber reinforced polymer composites have advantages over traditional continuous fiber composites, which include low cost and design flexibility.

Additively manufactured

short fiber reinforced polymer composites

continuous fiber composites

design flexibility


Input: However, these composites suffer from low strength and stiffness as compared to their continuous fiber counterparts due to the limitation of low fiber volume.

composites

as

continuous fiber

fiber

strength

stiffness


Input: This direct write additive manufacturing technique allowed us to fabricate short fiber reinforced thermoset composites in intricate geometries, with unprecedented high compression strength (673 MPa), flexural strength (401 MPa), flexural stiffness (53 GPa), and fiber volume ratio (46%).

additive manufacturing

fabricate

fiber

composites

fiber

geometries

MPa

MPa

compression strength

flexural strength

stiffness

GPa


Input: Milled carbon fibers were used as the reinforcing fibers, which were considered too short to have the ability to enhance the mechanical strength of composites.

Milled carbon fibers

as

reinforcing fibers

composites

mechanical strength


Input: However, in this study we show for the first time that milled carbon fibers have the ability to significantly reinforce the thermoset matrix and the composites reinforced with these fibers achieve mechanical performances similar to those of composites reinforced with longer fibers.

milled carbon fibers

composites

fibers

composites

fibers

mechanical


Input: We believe that a transformation takes place at high fiber volumes on the load transport mechanism within the composites, leading to higher levels of strength and a stiffness enhancement.

fiber

composites

transport

mechanism

strength

stiffness


Input: This pseudo transformation can give rise to short fibers that act as if they are longer, which aids in the effective transfer of tensile loads from the matrix phase to the fibers.

short fibers

as

fibers

tensile loads

phase


Input: This study also showed that the mechanical properties of the additively fabricated thermoset composites match those of ubiquitous, denser structural metals, and these properties show nearly isotropic behavior.

mechanical properties

fabricated

properties

composites

metals

isotropic


Input: Therefore, these systems have great potential to find immediate applications where weight reduction and component complexity are both desired.

weight

reduction

complexity

component


Input: Lattice structures are excellent candidates for lightweight, energy absorbing applications such as personal protective equipment.

Lattice structures

lightweight

as

equipment


Input: In this paper we explore several important aspects of lattice design and production by metal additive manufacturing, including the choice of cell size and the application of a post-manufacture heat treatment.

lattice design

production

metal additive manufacturing

heat treatment

cell size


Input: Key results include the characterisation of several failure modes in double gyroid lattices made of Al-Si10-Mg, the elimination of brittle fracture and low-strain failure by the application of a heat treatment, and the calculation of specific energy absorption under compressive deformation (16 × 106 J m−3 up to 50% strain).

failure modes

strain

lattices

brittle fracture

failure

specific energy absorption

deformation

heat treatment


Input: These results demonstrate the suitability of double gyroid lattices for energy absorbing applications, and will enable the design and manufacture of more efficient lightweight parts in the future.

lattices

manufacture

lightweight

design


Input: Minimizing the residual stress build-up in metal-based additive manufacturing plays a pivotal role in selecting a particular material and technique for making an industrial part.

residual stress

additive manufacturing

material

industrial


Input: In beam-based additive manufacturing, although a great deal of effort has been made to minimize the residual stresses, it is still elusive how to do so by simply optimizing the manufacturing parameters, such as beam size, beam power, and scan speed.

additive manufacturing

manufacturing

residual stresses

as

beam

scan speed