Input: The reduced cooling rate directly contributed to the decreased heterogeneous nucleation rate and the coarsening of austenite grains in the top domain.

cooling rate

heterogeneous nucleation

domain

austenite


Input: The differences in terms of microstructure and hardness of the as-fabricated samples along the building direction were also in a good agreement with the evolution of temperature field.

microstructure

samples

evolution

hardness

building direction

temperature


Input: The thermal cycling experimental and cyclic heat treatment results confirmed that in-situ thermal cycles were unable to trigger recrystallization because the stored strain energy was insufficient to induce nucleation of new austenite grains during laser directed energy deposition.

thermal cycling

experimental

in-situ

recrystallization

nucleation

heat treatment

laser directed energy deposition

strain

austenite


Input: Additive manufacture of sand molds via binder jetting enables the casting of complex metal geometries.

Additive manufacture

binder jetting

casting

sand

metal

molds

geometries


Input: Various material systems have been created for 3D printing of sand molds; however, a formal study of the materials’ effects on cast products has not yet been conducted.

Various material

sand

3D printing

cast

molds

materials


Input: In this paper the authors investigate potential differences in material properties (microstructure, porosity, mechanical strength) of A356–T6 castings resulting from two different commercially available 3D printing media.

material properties

microstructure

porosity

mechanical strength

3D printing


Input: In addition, the material properties of cast products from traditional “no-bake” silica sand is used as a basis for comparison of castings produced by the 3D printed molds.

material properties

cast

3D printed

silica sand

as


Input: It was determined that resultant castings yielded statistically equivalent results in four of the seven tests performed: dendrite arm spacing, porosity, surface roughness, and tensile strength and differed in sand tensile strength, hardness, and density.

dendrite

porosity

surface roughness

tensile strength

strength

hardness

density

sand


Input: As additive manufacturing (AM) advances rapidly towards new materials and applications, it is vital to understand the performance limits of AM technologies and to overcome these limits via improved machine design and process integration.

As

additive manufacturing

AM

AM technologies

materials

performance limits

limits

process

machine

design


Input: Extrusion-based AM (i.e., fused filament fabrication, FFF) is compatible with a wide variety of thermoplastic polymer and composite materials, and can be deployed across a wide range of length scales.

AM

fused filament fabrication

FFF

thermoplastic polymer

composite materials

be

range

length scales


Input: However, the build rate of both desktop and professional FFF systems is comparable (∼10’ s of cm3/h at ∼0.2 mm layer thickness), suggesting that fundamental aspects of the machine design and process physics limit system performance.

build rate

FFF

mm

s

layer thickness

machine

design

process physics

limit

performance


Input: We determine the rate limits to FFF by analysis of machine modules: the filament extrusion mechanism, the heater and nozzle, and the motion system.

limits

FFF

extrusion

machine

nozzle

filament


Input: We determine, by direct measurements and numerical analysis, that FFF build rate is influenced by the coincident module-level limits to traction force exerted on the filament, conduction heat transfer to the filament core, and gantry velocity for positioning the printhead.

FFF

build rate

limits

force

heat transfer

filament

filament

core


Input: Our findings are validated by direct measurements of build rate versus part complexity using desktop FFF systems.

build rate

complexity

FFF


Input: Last, we study the scaling of the rate limits using finite element simulations of thermoplastic flow through the extruder.

limits

finite element

thermoplastic

extruder


Input: We map the scaling of extrusion force, polymer exit temperature, and average printhead velocity onto a unifying trade-space of build rate versus resolution.

extrusion

polymer

temperature

resolution

average

build rate


Input: This approach validates the build rate performance of current FFF systems, and suggests that significant enhancements in FFF build rate with targeted quality specifications are possible via mutual improvements to the extrusion and heating mechanism along with high-speed motion systems.

build rate

build rate

FFF

FFF

extrusion

heating

quality


Input: The ability to design complex copper (Cu) parts into the most efficient thermal structures is an old dream, but difficult to realize with conventional manufacturing techniques.

design

copper

Cu

conventional manufacturing


Input: The recent development of laser 3D printing techniques makes it possible to fully explore intricate designs and maximize the thermal performance of Cu-based thermal management components but present significant challenges due to its high optical reflectivity.

laser

3D printing

designs

performance

components

optical


Input: In this study, we demonstrated the laser 3D printing of pure Cu with a moderate laser power (400 W).

laser

3D printing

Cu

laser power


Input: Dense Cu parts (95%) with smooth surface finishing (Ra ∼18 μm) were obtained at a scan speed of 400 mm/s, a hatch distance of 0.12 mm, and a layer thickness of 0.03 mm.

Cu

smooth surface

finishing

mm

mm

scan speed

hatch distance

layer thickness


Input: The hardness, electrical, and thermal conductivity of the printed Cu parts are 108 MPa, 5.71 × 107 S/m, and 368 W/m·K, respectively which are close to those of bulk Cu.

hardness

thermal conductivity

electrical

Cu

Cu

MPa


Input: Additionally, complex heat sink structures were printed with large surface areas (600 mm2/g), and their cooling performances were compared to a commercial heat sink with a smaller surface area (286 mm2/g) on an electronic chip.

heat sink

heat sink

surface areas

surface area

cooling

chip


Input: The complex heat sinks printed cools the electronic chip 45% more efficiently than the commercial one.

heat sinks

chip


Input: The introduction of selective laser melting to additively manufacturing Cu heat sinks offers the promise to enhance the performance beyond the scope of exciting thermal management components.

selective laser melting

manufacturing

Cu

performance

components


Input: Control of microstructure in a TiAl alloy was conducted by electron beam melting (82/85).

microstructure

alloy

electron beam melting


Input: An unique layered microstructure was created by the proposed EBM process (74/85).

microstructure

EBM


Input: The room temperature ductility was greater than 2% under an appropriate condition (83/85).

temperature

ductility


Input: As-EBM specimens exhibited high yield strength and good ductility at 800 °C (76/85).

yield strength

ductility


Input: This paper clarified a novel strategy to improve the tensile properties of the Ti-48Al-2Cr-2Nb alloys fabricated by electron beam melting (EBM), via the finding of the development of unique layered microstructure composed of duplex-like fine grains layers and coarser γ grains layers.

tensile properties

alloys

electron beam melting

EBM

microstructure

grains

grains


Input: It was clarified that the mechanical properties of the alloy fabricated by EBM can be controlled by varying an angle θ between EBM-building directions and stress loading direction.

mechanical properties

alloy

be

EBM

stress


Input: At room temperature, the yield strength exhibits high values more than 550 MPa at all the loading orientations investigated (θ = 0, 45 and 90°).

temperature

yield strength

MPa

orientations


Input: The anisotropy of the yield strength decreased with increasing temperature.

anisotropy

yield strength

temperature


Input: All the examined alloys exhibited a brittle-ductile transition temperature of approximately 750 °C and the yield strength and tensile elongation at 800 °C were over 350 MPa and 40%, respectively.By the detailed observation of the microstructure, the formation mechanism of the unique layered microstructure was found to be closely related to the repeated local heat treatment effect during the EBM process, and thus its control is further possible by the tuning-up of the process parameters.

alloys

be

transition

MPa

microstructure

mechanism

microstructure

process parameters

temperature

yield strength

tensile elongation

heat treatment

EBM


Input: The results demonstrate that the EBM process enables not only the fabrication of TiAl products with complex shape but also the control of the tensile properties associated with the peculiar microstructure formed during the process.

EBM

fabrication

complex shape

tensile properties

microstructure

process


Input: Ti-1Al-8V-5Fe (Ti-185) and other Fe containing β -Ti alloys are attractive because of their high strength and low cost.

Fe

alloys

strength


Input: These alloys, however, can not be produced through ingot casting due to strong Fe segregation and the formation of β flecks.

alloys

be

ingot

Fe

casting


Input: Selective Laser Melting (SLM) was successfully used to produce Ti-185 components starting from elemental Ti and Fe powders, and an Al-V master alloy powder with irregular shape.

Selective Laser Melting

SLM

components

Ti

Fe

alloy


Input: Microstructure analysis of the as-built components demonstrated that SLM can be used to produce a very fine grain microstructure with nano-scale precipitates and non-detrimental Fe segregation.

Microstructure

grain

nano-scale

components

SLM

be

Fe


Input: The findings are interpreted in terms of the rapid solidification conditions during SLM.

rapid solidification

SLM


Input: Compression test results reveal that ultra-high strength and reasonable ductility can be achieved in the as-built as well as heat treated samples.

Compression test

strength

ductility

be

as

as

samples


Input: Residual distortion is a major technical challenge for laser powder bed fusion (LPBF) additive manufacturing (AM), since excessive distortion can cause build failure, cracks and loss in structural integrity.

Residual distortion

distortion

laser powder bed fusion

LPBF

additive manufacturing

AM

build failure

structural integrity


Input: However, residual distortion can hardly be avoided due to the rapid heating and cooling inherent in this AM process.

residual distortion

be

heating

cooling

AM process


Input: Thus, fast and accurate distortion prediction is an effective way to ensure manufacturability and build quality.

accurate

prediction

manufacturability

build


Input: This paper proposes a multiscale process modeling framework for efficiently and accurately simulating residual distortion and stress at the part-scale for the direct metal laser sintering (DMLS) process.

process modeling

framework

residual distortion

process

accurately

stress

direct metal laser sintering

DMLS


Input: In this framework, inherent strains are extracted from detailed process simulation of micro-scale model based on the recently proposed modified inherent strain model.

framework

extracted

micro-scale

model

process simulation

strain


Input: The micro-scale detailed process simulation employs the actual parameters of the DMLS process such as laser power, velocity, and scanning path.

micro-scale

parameters

scanning

process simulation

DMLS

as

power


Input: Uniform but anisotropic strains are then applied to the part in a layer-by-layer fashion in a quasi-static equilibrium finite element analysis, in order to predict residual distortion/stress for the entire AM build.

anisotropic

layer-by-layer fashion

quasi-static equilibrium finite element analysis

residual

AM


Input: Effectiveness of this proposed framework is demonstrated by simulating a double cantilever beam and a canonical part with varying wall thicknesses and comparing with experimental measurements which show very good agreement.

Effectiveness

framework

experimental

cantilever beam

wall thicknesses


Input: The metallurgy of selected metal and alloy components fabricated by additive metallurgy using electron beam melting (EBM) is presented for a range of examples including Ti-6Al-4V, Co-Cr-Mo super alloy, Ni-base super alloy systems (Inconel 625, 718 and Rene 142), Nb and Fe.

metallurgy

fabricated

metal

alloy

additive

super alloy

super alloy

Inconel 625

Rene

Nb

Fe

electron beam melting

EBM

range


Input: Precursor and pre-alloyed powders are preheated and selectively melted using a range of EBM process parameters including beam scan strategies, beam current variations, and cooling rate features.

Precursor

powders

melted

parameters

variations

range

cooling rate

EBM

beam

beam


Input: Microstructures and residual mechanical properties are discussed for selected systems in contrast to more conventional wrought and cast products.

Microstructures

residual mechanical properties

wrought

cast


Input: Novel features of EBM fabrication include columnar microstructural architectures which result by layer-by-layer melt-solidification phenomena.

EBM

microstructural

layer-by-layer


Input: Combining electrical and magnetic materials in the same part has been a challenge in 3D printing due to difficulties co-printing complex materials in many additive manufacturing processes.

electrical

materials

materials

3D printing

additive manufacturing processes


Input: Past 3D printed inductors and other similar magnetic devices have therefore either lacked the magnetic materials necessary for improved performance, or required sintering at high temperatures for extended periods, beyond the capability of most 3D printable polymers.

3D printed

sintering

materials

performance

temperatures

polymers


Input: In this work, we demonstrate a room temperature process for incorporating conductive and magnetic materials into the same 3D printed device.

temperature

process

materials

3D printed


Input: A multi-stage fabrication process based on 3D printing followed by fill with magnetic and conductive fluids is proposed.

fabrication

3D printing

fluids


Input: Multi-layer microfluidic channels for magnetic passives are first printed in a stereolithography process.

stereolithography

process


Input: The microfluidic systems are then filled with room temperature liquid metal, a gallium alloy liquid at room temperature, and ferrofluid to create inductors, transformers and wireless power coils.

temperature

temperature

power

liquid metal

gallium

alloy


Input: 3D finite element modeling of LSFF process is presented based on a moving mesh approach.

process

element


Input: Temporal behaviors of stress fields and temperature distributions are explored for different deposited layers.

stress

temperature

distributions

deposited layers


Input: Effects of preheating and addition of nano particles are thoroughly investigated.

preheating

nano


Input: Scanning velocity of the laser plays a key role on the clad shape.

Scanning

laser


Input: Gas turbine blades, turbine shafts and centrifugal compressor impellers are often damaged by erosion and/or corrosion.

Gas turbine

corrosion


Input: By laser cladding technique, a coating layer can be deposited on the base material in order to rebuild, repair and improve anti-erosion or anti-corrosion properties of the sensitive machine parts.

laser cladding

coating

be

material

properties

machine


Input: In this paper, a three-dimensional finite element modeling of the laser solid freeform fabrication (LSFF) process for nickel alloy 625 powder mixed with nano-CeO2 on AISI 4140 steel is extensively studied.

three-dimensional

finite element

process

laser

freeform fabrication

nickel alloy

powder

steel


Input: Using Comsol Multiphysics software and the finite element method (FEM), the heat transfer equation, moving mesh equation and stress tensor are numerically solved.

software

finite element method

FEM

heat transfer

stress


Input: Clad shape, temperature distribution and stress fields are obtained.

temperature

distribution

stress


Input: The effects of preheating as well as addition of nano-CeO2 are investigated.

preheating

as

as


Input: Dependence of the clad height on the scanning velocity of the laser is also studied.

scanning

laser


Input: This paper demonstrates the ability to 3D print a fluoropolymer based energetic material which could be used as part of a multifunctional reactive structure.

3D print

material

be

as

structure


Input: The work presented lays the technical foundation for the 3D printing of reactive materials using fusion based material extrusion.

3D printing

material extrusion

reactive materials

fusion


Input: A reactive filament comprising of a polyvinylidene fluoride (PVDF) binder with 20% mass loading of aluminum (Al) was prepared using a commercial filament extruder and printed using a Makerbot Replicator 2X.

filament

binder

aluminum

Al

filament

extruder


Input: Printing performance of the energetic samples was compared with standard 3D printing materials, with metrics including the bead-to-bead adhesion and surface quality of the printed samples.

Printing performance

samples

standard

samples

3D printing

adhesion

surface quality


Input: The reactivity and burning rates of the filaments and the printed samples were comparable.

filaments

samples


Input: Differential scanning calorimetry and thermal gravimetric analysis showed that the onset temperature for the reactions was above 350 °C, which is well above the operation temperature of both the filament extruder and the fused deposition printer.

scanning

fused deposition

temperature

temperature

filament

extruder


Input: A lattice Boltzmann (LB) method to simulate melt pool dynamics and a cellular automaton (CA) to simulate the solidification process are coupled to predict the microstructure evolution during selective electron beam melting (SEBM).

lattice

microstructure evolution

melt pool

CA

solidification process

selective electron beam melting

SEBM


Input: The resulting CALB model takes into account powder related stochastic effects, energy absorption and evaporation, melt pool dynamics and solidification microstructure evolution.

model

stochastic

evaporation

solidification microstructure

evolution

powder

melt pool

energy absorption


Input: Several physical phenomena are observed during grain solidification, e.g., initial grain selection starting at the base plate, grain boundary perturbation, grain nucleation due to unmolten powder particles in the bulk, grain penetration from the surface of the part or grain alignment dependent on the beam scanning strategy.

grain

grain

grain boundary

grain

grain

surface

grain

powder particles

beam


Input: The effect of process parameters on the final grain structure and texture evolution is presented.

process parameters

grain structure

evolution

texture


Input: Manufacturing of ceramic components with a geometrically complex 3D architecture and highly detailed features for use in a variety of practical applications is still a challenge.

Manufacturing

ceramic


Input: In our investigation, we adopted a synergistic strategy for fabricating SiOC ceramics with intricate 3D morphologies by additive manufacturing and origami technique or assemblage, taking advantage of the high printability and flexibility of a commercially available silicone elastomer.

fabricating

additive manufacturing

ceramics

silicone elastomer

printability

flexibility


Input: Secondary shaping using origami of different 2D layers with varied design allowed the manufacturing of spiral, flower-like and polyhedron architectures, which are difficult to fabricate without adding supports or by any conventional ceramic fabrication processes.

shaping

manufacturing

fabricate

processes

design

supports

ceramic


Input: Produced samples showed no cracks or pores and fully retained the given shape after pyrolysis.

samples

pores

pyrolysis


Input: Origami-assisted 3D printing enables easy fabrication of complex SiOC ceramic structures without requiring any supports.

3D printing

fabrication

ceramic

supports


Input: The potential of adding fillers into the silicone material used in this work could expand the applicability of the manufactured structures introducing additional functional properties.Download: Download high-res image (212 The aim of this paper is to investigate the evolution of a matrix-filler interface during the processing of novel composites formed by a matrix of polylactic acid (PLA) and Mg particles, when they are manufactured by Materials Extrusion.

silicone material

composites

polylactic acid

PLA

Mg

manufactured

high-res image

evolution

interface

manufactured

Materials

Extrusion


Input: The particles addition to the PLA was carried out through the preparation of a Magnesium stable suspension in the polymer solution.

particles

PLA

Magnesium

polymer


Input: To improve the Mg dispersion, the surfaces of the particles were previously modified by the adsorption of dispersants, namely Polyethylenimine (PEI) and Cetyltrimethylammonium bromide (CTAB) in aqueous suspension.

Mg

dispersion

surfaces

particles

adsorption


Input: The physical and mechanical characterization of PLA/Mg composites show that the Mg surface modification is the key to its successful dispersion due to the formation of ionic interactions between the dispersants and the matrix.

mechanical

composites

Mg

dispersion


Input: This is favoured by the seeding effect of the PEI-modified Mg particles over the PLA re-precipitation during the composite shaping.

Mg

PLA

composite


Input: Moreover, a PEI-PLA covalent bond appeared in the printed scaffolds as a consequence of the temperature applied (165 °C) during extrusion and printing.

covalent bond

scaffolds

as

temperature

extrusion


Input: Consequently, the matrix-filler strengthened interface improved the extrusion process and permits the printing of 3D customized pieces.

interface

extrusion process


Input: At the same time, particle agglomeration and the nozzle blocking is prevented.

particle

blocking

nozzle


Input: To reveal the mechanism of oxidation and the effect of inclusion characteristics on the mechanical properties of additively-manufactured metal matrix, two groups of AISI 316 L stainless steel samples were fabricated under different flow rates of shielding gas (Ar) at two intensities of laser beam.

mechanism

mechanical properties

metal matrix

samples

fabricated

gas

laser beam

oxidation

inclusion

stainless steel

flow rates

Ar


Input: As flow rates of shielding gas increased from 5 L/min to 25 L/min, the oxygen content in the melt pool decreased from 775 ppm to 375 ppm at low intensity of laser beam (73 W/m2), and from 677 ppm to 1470 ppm at high intensity of laser beam (725 W/m2).

As

oxygen

melt pool

gas

laser beam

laser beam


Input: Variation in oxygen content affected melt pool shape, solidification texture, and the mechanical properties of the material.

Variation

solidification

mechanical properties

oxygen

melt pool

material


Input: In each intensity of laser beam group, optimal flow rates of shielding gas condition for tensile property existed.

laser beam

gas

flow rates

tensile property


Input: As inclusion number density increased from 8866/mm2 to 45909/mm2, yield stress increased to 26%.

As

density

yield stress


Input: A rapid drop in ductility occurred at flow rate 5 L/min, because independently-nucleated spinel accelerated inclusion coalescence in the melt pool.

ductility

flow rate

spinel

inclusion

melt pool


Input: Directed energy deposition (DED) is a metal additive manufacturing process, where dimensional accuracy and repeatability are traditionally challenging to achieve.

Directed energy deposition

DED

metal additive manufacturing

dimensional accuracy

repeatability


Input: Strategies for computationally inexpensive process modelling and fast-response process controls of the laser deposition process are necessary to keep the geometric features close to the required dimensional tolerances.

process

process controls

modelling

laser

deposition process

dimensional tolerances


Input: The deposition geometry depends highly on the complex local laser-material interaction and global thermal history of the substrate.

deposition

substrate


Input: In order to control the deposition geometry, an accurate and computationally inexpensive discretized state space thermal history model coupled with an analytical deposition geometry model is developed in this work.

deposition

model

deposition

model

accurate


Input: The model accounts for the local laser-material interaction using the mass and energy equilibrium equations coupled in a lumped parameter solution, as well as the global thermal history of the product using a state space thermomechanical discretization.

model

equilibrium

parameter

thermomechanical

as

as


Input: In literature, studies have only focused on 1D toolpaths with constant process parameters such as speed, powder feedrate, and laser power.

process parameters

as

powder

laser power


Input: As it is possible to achieve highly complex geometric shapes with additive manufacturing, it is important to have models compatible with 2D/3D complex toolpaths.

As

geometric shapes

additive manufacturing


Input: In this paper, an analytical thermomechanical model and a coupled deposition geometry model for DED process are presented and experimentally validated.

thermomechanical model

deposition

model

experimentally validated

DED


Input: As such, the thermal history of the deposited part is predicted throughout the process and the geometric features are predicted for 2D toolpaths.

As

predicted

process

predicted


Input: Despite the ongoing success of metal additive manufacturing and especially the selective laser melting (SLM) technology, process-related defects, distortions and residual stresses impede its usability for fracture-critical applications.

metal additive manufacturing

selective laser melting

SLM

technology

defects

residual stresses


Input: In this paper, results of in situ X-ray diffraction experiments are presented that offer insights into the strain and stress formation during the manufacturing of multi-layer thin walls made from Inconel 625.

in situ

diffraction

strain

stress

manufacturing

Inconel 625


Input: Using different measuring modes and laser scanning parameters, several experimental observations are discussed to validate and extend theoretical models and simulations from the literature.

laser

simulations

parameters

experimental

theoretical models


Input: As a sample is built-up layer by layer, the stress state changes continuously up until the last exposure.

As

sample

layer by layer

exposure

stress


Input: The localized energy input leads to a complex stress field around the heat source that involves alternating tensile and compressive stresses.

stress

tensile

compressive stresses

heat source


Input: The correlation of temperature and yield strength results in a stress maximum at a certain distance to the top layer.

temperature

layer

yield strength

stress


Input: The present study demonstrates the potential of high-energy synchrotron radiation diffraction for in situ SLM research.

synchrotron

radiation

diffraction

in situ

research


Input: Fabry-Pérot ultrasonic metamaterials have been additively manufactured using laser powder bed fusion to contain subwavelength holes with a high aspect-ratio of width to depth.

metamaterials

additively manufactured

laser powder bed fusion


Input: Such metamaterials require the acoustic impedance mismatch between the structure and the immersion medium to be large.

metamaterials

be

structure


Input: It is shown for the first time that metallic structures fulfil this criterion for applications in water over the 200–800 kHz frequency range.

metallic structures

range


Input: It is also demonstrated that laser powder bed fusion is a flexible fabrication method for the ceration of structures with different thicknesses, hole geometry and tapered openings, allowing the acoustic properties to be modified.

laser powder bed fusion

fabrication

geometry

properties

be


Input: It was confirmed via both finite element simulation and practical measurements that these structures supported Fabry-Pérot resonances, needed for metamaterial operation, at ultrasonic frequencies in water.

finite element

metamaterial


Input: Selective electron beam melting (SEBM) is shown to be a viable production route for titanium aluminides components.

Selective electron beam melting

SEBM

production

be

titanium

components


Input: Fully dense and crack free parts can be produced.

Fully dense

be


Input: In the present paper a titanium aluminide alloy Ti-45Al-4Nb-C was investigated and the complete processing chain was developed, i.e.

titanium aluminide alloy


Input: starting from the determination of the processing window, the evaluation of corresponding material properties for cube like specimens and finally the production of turbocharger wheels.

material properties

cube

production


Input: The material properties were optimized by adjusting scanning strategy as well as heat treatment with particular consideration of the application to turbocharger wheels.

material properties

scanning strategy

as

as


Input: The issue of dimensional accuracy and the feasibility of joining will be discussed and a proof test is performed.

dimensional accuracy

feasibility

joining

be


Input: Cobalt-chromium-molybdenum (CoCrMo) alloys are widely used in load-bearing implants; specifically, in hip, knee, and spinal applications due to their excellent wear resistance.

alloys

load-bearing

implants

hip

knee

wear resistance


Input: However, due to in vivo corrosion and mechanically assisted corrosion, metal ion release occurs and accounts for poor biocompatibility.

corrosion

corrosion

ion

metal

biocompatibility


Input: Therefore, a significant interest to improve upon CoCrMo alloy exists.

CoCrMo alloy


Input: In the present work we hypothesize that calcium phosphate (CaP) will behave as a solid lubricant in CoCrMo alloy under tribological testing, thereby minimizing wear and metal ion release concerns associated with CoCrMo alloy.

calcium phosphate

as

lubricant

CoCrMo alloy

metal

CoCrMo alloy

tribological

wear

ion

testing


Input: CoCrMo-CaP composite coatings were processed using laser engineered net shaping (LENS™) system.

composite coatings

processed

laser engineered net shaping


Input: After LENS™ processing, CoCrMo alloy was subjected to laser surface melting (LSM) using the same LENS™ set-up.

CoCrMo alloy

LSM

laser

melting


Input: Samples were investigated for microstructural features, phase identification, and biocompatibility.

Samples

microstructural

phase

biocompatibility


Input: It was found that LSM treated CoCrMo improved wear resistance by 5 times.

LSM

wear resistance


Input: Our results show that careful surface modification treatments can simultaneously improve wear resistance and in vivo biocompatibility of CoCrMo alloy, which can correlate to a reduction of metal ion release in vivo.

surface modification

wear resistance

biocompatibility

CoCrMo alloy

metal

reduction

ion


Input: Additive manufacturing (AM) has several possible advantages over traditional manufacturing including increased design freedom, reduced material usage, and shorter lead-times.

Additive manufacturing

AM

traditional manufacturing

design freedom

material


Input: A noteworthy capability of AM is the ability to monitor the process during material deposition and interrupt the process during fabrication if necessary.

AM

fabrication

monitor

process

deposition

process

material


Input: Recently, such monitoring, feedback, and control have been made possible by implementing in situ infrared (IR) thermography in powder bed fusion AM technologies.

feedback

in situ

IR

powder bed fusion AM technologies


Input: The purpose of the current research was to investigate the acquisition of absolute surface temperatures using in situ IR imaging of the melted or solid surfaces layer-by-layer during fabrication within an electron beam melting (EBM) system.

research

surface

in situ

melted

surfaces layer-by-layer

imaging

fabrication

electron beam melting

EBM


Input: The thermal camera was synchronized with the system's signal voltages of three synchronized events (pre-heating, melting, and raking) to automatically capture images.

camera

melting

images


Input: To acquire absolute temperature values from the IR images, a calibration procedure was established to determine the solid material's emissivity and reflected temperature or mean radiant temperature of the build chamber, which are necessary input parameters for the IR camera.

temperature

temperature

temperature

build chamber

IR

IR

images

calibration

parameters

material

camera


Input: A blackbody radiator was fabricated via EBM and was used as a tool to determine the emissivity of Ti–6Al–4V (determined to be 0.26 in the temperature range of the current study).

fabricated

EBM

as

be

tool

temperature range


Input: heat shielding) that were used in calculating the mean radiant temperature of the manufacturing environment (∼342 °C).

heat

temperature

manufacturing


Input: Experimental validation of the model was performed using a thermocouple embedded during fabrication that showed a 3.77% difference in temperature.

Experimental

model

thermocouple

fabrication

temperature


Input: A temperature difference of ∼366 °C (1038 °C vs. 672 °C) was observed when comparing uncorrected IR temperature data with corrected temperature data.

temperature

temperature

IR

data

data


Input: Upon validation of the IR parameters for a melted area, experimentation was conducted to also determine powder emissivity (found to be 0.50).

validation

melted

IR

area

powder

be


Input: The thermal model presented here can be modified and implemented in other AM technologies for consideration of radiation energy to acquire absolute temperatures of layered surfaces, leading to improved thermal monitoring and control of the fabrication process.

model

surfaces

be

AM technologies

radiation

fabrication

temperatures


Input: In-situ welding during powder bed fusion additive manufacturing process was proposed.

In-situ

powder bed fusion additive manufacturing


Input: Highly dense part without degrading of mechanical properties was fabricated by EBM.

mechanical properties

fabricated

EBM


Input: The applications of EBM technology was expanded using the in-situ welding concept.

EBM

in-situ


Input: As one of the powder-bed-fusion additive manufacturing processes, electron beam melting (EBM) is able to produce metal parts directly.

As

metal

additive manufacturing processes

electron beam melting

EBM


Input: Many small volume components with high quality have been fabricated using the EBM technology.

volume

quality

fabricated

components

EBM


Input: However, there are only few reports on the EBM fabrication of medium-sized components.

EBM

components


Input: This, in turn, drastically degrades the mechanical properties of the EBM printed parts.

mechanical properties

EBM


Input: Here, we firstly report an in-situ welding process to overcome the lack of energy issue caused by the long scan length during EBM process.

in-situ

process

EBM


Input: After the investigation of the corresponding microstructure, microhardness and tensile properties, it is revealed that the in-situ welding zone is fully joined and the mechanical properties of the in-situ welded part are comparable to that of the wrought counterpart.

microstructure

microhardness

in-situ

mechanical properties

in-situ

wrought

tensile properties


Input: This implies that medium-sized components can be successfully fabricated using the EBM, with no compromise on the mechanical properties.

components

be

fabricated

mechanical properties

EBM


Input: From pottery to clay tablets and building materials, clay easily qualifies as one of the most versatile materials in the history of human civilization.

clay

clay

as

materials

materials


Input: Clay owes this versatility to the distinct properties it exhibits before and after firing.

Clay

properties

firing


Input: Soft, unfired clay can morph into complex shapes, while fired clay offers a fixed shape and higher stiffness.

clay

clay

complex shapes

stiffness

fired


Input: Despite several potential applications, thus far, no designer materials with similar properties have been demonstrated.

materials

properties


Input: Here, we introduce the concept of metallic clay: a designer material that mimics the two-state behavior of clay.

metallic clay

material

clay


Input: Metallic clay could initially morph into arbitrarily complex shapes owing to numerous degrees-of-freedom that its various kinematic (moving) and compliant (deformable) joints afford.

Metallic clay

complex shapes


Input: The fabrication of metallic clay requires novel designs of joints and locking mechanisms that are compatible with metal 3D printing (additive manufacturing) techniques such that metallic clay can be fabricated through a single-step, non-assembly, and self-supporting 3D printing process.

fabrication

3D printing

additive manufacturing

3D printing

metallic clay

metal

metallic clay

be

designs

self-supporting


Input: We designed with 3D printing 17 prototypes using selective laser melting from a medical grade high strength titanium alloy (Ti-6Al-4V) to demonstrate the various aspects of metallic clay.

designed

3D printing

selective laser melting

prototypes

medical

strength

alloy

metallic clay


Input: Biomass-derived polymers have been rapidly developed for alleviating excessive fossil-fuel-based plastic consumption, as green manufacturing is required due to many environmental issues.

polymers

plastic

as

manufacturing

environmental issues


Input: Here, using a recently developed biopolymer, bio-based polycarbonate (bio PC), we demonstrated the processability of filament-feedstock extrusion and extrusion-type 3D printing.

biopolymer

polycarbonate

PC

extrusion

3D printing


Input: Under a set of optimal process conditions, the as-printed bio PC products showed superior tensile strength compared to other commercial polymers.

set

optimal process

PC

polymers

tensile strength


Input: We also confirmed the environmentally friendly characteristics of the thermoplastic processes of bio PC by measuring hazardous emissions during 3D printing.

thermoplastic

PC

processes

3D printing


Input: Finally, considering sterilization of the as-printed consumer products, we tested the resistive properties of bio PC parts against heat and UV.

consumer products

properties

heat

UV

PC


Input: Collectively, the good 3D printability, low gas and particle emission, and decent durability of the bio PC material indicate great potential applications for indoor home manufacturing of various consumer products.

gas

particle

emission

durability

PC material

manufacturing

consumer products


Input: Process−property relationships in additive manufacturing (AM) play critical roles in process control and rapid certification.

additive manufacturing

AM

process control


Input: In laser-based directed energy deposition, powder mass flow into the melt pool influences the cooling behavior and properties of a built part.

directed energy deposition

cooling

powder

melt pool

properties


Input: This study develops predictive computational models that provide the microhardness of AM components processed with miscible dissimilar alloys, and then investigates the influence of varying process parameters on properties in experiments and modeling.

computational models

modeling

microhardness

processed

investigates

process parameters

properties

AM

dissimilar alloys


Input: Experimentally-determined clad dilution and microhardness results of Ni-based superalloy Inconel 718 clads deposited onto 1045 carbon steel substrates are compared to the values from a computational thermo-fluid dynamics (CtFD) model.

microhardness

model

Inconel 718

carbon steel


Input: The numerical model considers the fluidic mechanisms of molten metal during powder deposition and the resulting transient melt pool geometry changes.

model

deposition

transient

geometry

molten metal

powder

melt pool


Input: The model also handles the change in thermo-physical properties caused by the composition mixture between the powder and substrate materials in the melt pool.

model

properties

composition

powder

substrate materials

melt pool


Input: Based on the computed temperature and velocity distributions in the melt pool, cooling rate, dilution of the melt pool and microhardenss are evaluated.

temperature

cooling rate

distributions

melt pool

melt pool


Input: The capability to predict thermal histories in such models is calibrated and validated with experimental thermal imaging and microstructures of additive manufactured clads.

calibrated

experimental

imaging

microstructures

additive manufactured


Input: In addition, the roles of cooling rate and alloy composition on the microhardness are examined.

cooling rate

alloy

microhardness


Input: The results show that variation in microhardness is dominated by composition mixture between the powder and substrate materials, rather than cooling behavior or dendrite arm spacing at liquid-solid interface in laser deposited Inconel 718 on AISI 1045 carbon steel.

variation

microhardness

composition

liquid-solid interface

powder

substrate materials

Inconel 718

carbon steel

cooling

dendrite

laser


Input: A new one-way coupled thermal-mechanical finite element based model of direct metal laser sintering (DMLS) is developed to simulate the process, and predict distortion and cracking failure location in the fabricated components.

finite element

model

process

distortion

cracking

fabricated

direct metal laser sintering

DMLS

components


Input: The model takes into account the layer-by-layer additive manufacturing features, solidification and melting phenomena.

model

layer-by-layer

solidification

additive manufacturing

melting


Input: The model is first validated using experimental data, then model is applied to a DMLS fabricated component.

model

experimental data

model

DMLS

component


Input: The study shows how the stress distribution at the support-solid interface is critical to contributing to cracking and distortion.

stress distribution

interface

cracking

distortion


Input: During the DMLS process, thermal stress at the support-solid interface reaches its maximum during the printing process, particularly when the first solid layer is built above the support layer.

DMLS

printing process

thermal stress

interface

layer

layer

support


Input: This result suggests that cracking at the interface may occur during the printing process, which is consistent with experimental observation.

cracking

interface

experimental

printing process


Input: Using a design parametric study, a thick and low-density porous layer is found to reduce residual stress and distortion in the built component.

design

porous

residual stress

layer

distortion

component


Input: The developed finite element model can be used to future design and optimize DMLS process.

finite element model

be

design

DMLS


Input: There is growing interest in Laser Powder Bed Fusion (L-PBF) or Selective Laser Melting (SLM) manufacturing of high conductivity metals such as copper and refractory metals.

Laser Powder Bed Fusion

L-PBF

Selective Laser Melting

SLM

manufacturing

conductivity

as

refractory metals


Input: SLM manufacturing of high thermal conductivity metals is particularly difficult.

SLM manufacturing

thermal conductivity

metals


Input: In case of refractory metals, the difficulty is amplified because of their high melting point and brittle behaviour.

refractory metals

melting point

brittle


Input: Rapid process development strategies are essential to identify suitable process parameters for achieving minimum porosities in these alloys, yet current strategies suffer from several limitations.

process

process parameters

porosities

alloys


Input: We propose a simple approach for rapid process development using normalized process maps.

simple

process

process


Input: Using plots of normalized energy density vs. normalized hatch spacing, we identify a wide processability window.

energy density

hatch spacing


Input: This is further refined using analytical heat transfer models to predict melt pool size.

heat transfer

melt pool


Input: Final optimization of the parameters is achieved by experiments based on statistical Design of Experiments concepts.

optimization

parameters

Design of Experiments


Input: In this article we demonstrate the use of our proposed approach for development of process parameters (hatch spacing, layer thickness, exposure time and point distance) for SLM manufacturing of molybdenum and aluminium.

process parameters

exposure

hatch spacing

layer thickness

SLM manufacturing

molybdenum

aluminium


Input: Relative densities of 97.4% and 99.7% are achieved using 200 W pulsed laser and 400 W continuous laser respectively, for molybdenum and aluminium, demonstrating the effectiveness of our approach for SLM processing of high conductivity materials.

Relative densities

conductivity

pulsed laser

SLM

laser

molybdenum

aluminium

effectiveness


Input: Inconel 718, a widely used nickel based super alloy, is of special interest to the aerospace and automotive fields for its highly desirable and consistent material properties over a large range of temperatures.

Inconel 718

nickel

super alloy

aerospace

automotive

material properties

range

temperatures


Input: The objective of this research is to understand the effect of process parameters of a Direct Metal Laser Sintering (DMLS) machine, concerning mainly beam power between 40 W and 300 W and scan line speed between 200 mm/s and 2500 mm/s on scan line quality, line geometry and dimensions, and melt pool geometry in laser melted Inconel 718 line scans.

research

process parameters

quality

geometry

geometry

Direct Metal Laser Sintering

DMLS

machine

beam

dimensions

melt pool

Inconel 718

laser


Input: Higher power runs resulted in voids forming in the bottom of the melt pool and were consistent with either electron beam welding or melting processes operating at higher temperatures.

power

temperatures

voids

forming

electron beam welding

melting

melt pool


Input: Laser energy density (LED), a method of correlating the effects of scan speed and beam power into one characteristic process parameter, was also investigated.

Laser energy density

scan speed

LED

beam

process parameter


Input: This ratio of beam power to scan speed follows a second order polynomial trend line for melt pool width and a logarithmic trend for average line width.

beam

scan speed

trend

trend

average

melt pool


Input: LED values for melt pool depth are separated to show two trend lines as two mechanisms operate at low values below 0.25 J/mm and high values above 0.25 J/mm.

LED

melt pool depth

trend

as


Input: Process optimization has always been a crucial step for effective usage of metal additive manufacturing (AM) processes: it consists in establishing quantitative relations between final part's characteristics and process parameters to find their optimal combination and obtain a fully functional mechanical component.

Process optimization

step

processes

quantitative

process parameters

metal additive manufacturing

AM

mechanical

component


Input: Experimental investigation techniques are usually employed for this purpose but they can be extremely expensive and time-consuming, especially when the output of the process depends on a large number of parameters, like for AM.

Experimental

process

parameters

be

AM


Input: Numerical simulation could represent an alternative solution: by reproducing the real process characteristics, a simulation could provide useful insights, allowing to evaluate the performance of the process for different parameter combinations without relying exclusively on expensive experimental campaigns.In this work, a finite element AM simulation based on the inherent strain (IS) method was developed and the prediction performance in terms of part's residual deformation was evaluated by comparing the numerical results with the measurements carried out on an experimental campaign.

Numerical simulation

simulation

solution

process

performance

process

parameter

experimental

finite element

prediction performance

residual deformation

experimental

AM

strain


Input: A new model calibration approach for prediction improvement was also implemented and it allowed to discover an unexpected behaviour of the model that strongly affects the validity of this method for AM simulation.

model calibration

prediction

model

AM


Input: The role of volumetric energy density on the microstructural evolution, texture and mechanical properties of 304L stainless steel parts additively manufactured via selective laser melting process is investigated.

energy density

microstructural evolution

mechanical properties

texture

stainless steel

additively manufactured

selective laser melting process


Input: 304L is chosen because it is a potential candidate to be used as a matrix in a metal matrix composite with nanoparticles dispersion for energy and high temperature applications.

be

as

metal matrix composite

nanoparticles dispersion

temperature


Input: The highest relative density of 99% ±0.5 was achieved using a volumetric energy density of 1400 J/mm3.

relative density

energy density


Input: Both XRD analysis and Scheil simulation revealed the presence of a small trace of the delta ferrite phase, due to rapid solidification within the austenitic matrix of 304L.

XRD

simulation

ferrite

austenitic

rapid solidification


Input: A fine cellular substructure ranged between 0.4–1.8 μm, was detected across different energy density values.

energy density


Input: At the highest energy density value, a strong texture in the direction of [100] was identified.

energy density

texture


Input: At lower energy density values, multicomponent texture was found due to high nucleation rate and the existing defects.

energy density

texture

nucleation

defects


Input: Yield strength, ultimate tensile strength, and microhardness of samples with a relative density of 99% were measured to be 540 ± 15 MPa, 660 ± 20 MPa and 254 ± 7 HV, respectively and higher than mechanical properties of conventionally manufactured 304L stainless steel.

Yield strength

ultimate tensile strength

relative density

microhardness

samples

MPa

MPa

mechanical properties

manufactured

be

stainless steel


Input: Heat treatment of the laser melted 304L at 1200 °C for 2 h, resulted in the nucleation of recrystallized equiaxed grains followed by a decrease in microhardness value from 233 ± 3 HV to 208 ± 8 HV due to disappearance of cellular substructure.

Heat treatment

recrystallized

laser

nucleation

equiaxed grains

microhardness


Input: In this work the process of Acoustoplastic Metal Direct-write (AMD) is introduced for the first time.

process

Metal


Input: Millimeter-scale 3D aluminum articles were printed to demonstrate the process feasibility.

process feasibility


Input: Evidence of process-induced inter-layer and intra-layer mass transport resulting in metallurgical bonding across voxels was obtained.

transport

metallurgical bonding

voxels


Input: During voxel formation, a process temperature rise of 5 ° Celsius from a process ambient temperature of 25 ° Celsius was recorded.

voxel

process

process

temperature


Input: In addition, acoustic energy-induced microstructural changes during process were observed in the material.

microstructural

process

material


Input: The work presented here not only demonstrates the feasibility of a new non-melt fusion room temperature metal 3D printing approach—capable of producing metals with more than 99 percent density—but also presents both observational study and an initial theoretical basis upon which a new athermal microstructural transformation process may be understood Selective laser melting and other additive manufacturing (AM) techniques have recently attracted substantial interest of both researchers and the processing industry.

feasibility

fusion

theoretical

microstructural

process

temperature

metal

metals

be

3D printing

Selective laser melting

additive manufacturing

AM

industry


Input: In the selective laser melting (SLM) process, the components are produced layer-wise using a laser beam.

selective laser melting

SLM

process

laser beam

components


Input: SLM is a powder bed based AM process and is characterized by the complete melting of the utilized powder material.

SLM

AM process

melting

powder bed

powder material


Input: Employing SLM, complex three-dimensional parts and light weight structures can be produced directly from 3D CAD data.

SLM

three-dimensional

data

weight

be


Input: However, although SLM is a very promising technology, there are still challenges to solve.

SLM

technology


Input: Under cyclic loading, pores can act as stress raisers and lead to premature crack initiations, which reduce the fatigue strength of the material.

cyclic loading

pores

fatigue strength

as

lead

material


Input: Hot isostatic pressing (HIP) offers the possibility to reduce the porosity.

Hot isostatic pressing

HIP

porosity


Input: HIP combines high pressure and high temperature to produce materials with superior properties.

HIP

pressure

materials

properties

temperature


Input: The influence of the HIP process parameters on the density and microstructure of IN718 SLM components is investigated by means of micro X-ray computed tomography and scanning electron microscopy.

HIP

parameters

microstructure

density

components

X-ray computed tomography

scanning electron microscopy


Input: The results of the experiments show that the majority of pores can be densified by means of HIP.

pores

be

HIP


Input: On the other hand, some pores can not be densified.

pores

be


Input: The reason for this is seen in entrapped argon gas from the SLM process.

argon

SLM

process


Input: Laser powder bed fusion (LPBF) additive manufacturing technology is sensitive to variations in powder particle morphology and size distribution.

Laser powder bed fusion

LPBF

additive manufacturing

variations

morphology

distribution

powder particle


Input: However, the absence of a clear link between the powder characteristics and the LPBF performances complicates the development, selection and quality control of LPBF powder feedstock.

powder

feedstock

LPBF

LPBF

quality control


Input: In this work, three Ti-6Al-4 V powder lots produced by two different techniques, namely, plasma atomization and gas atomization, were selected and characterized.

Ti-6Al-4 V powder

plasma

atomization

gas atomization


Input: Following the micro-computed tomography analysis of the powder particles’ morphology, size and density, the flowability of these powder lots was concurrently evaluated using Hall and Gustavsson flowmeters and an FT4 powder rheometer.

micro-computed tomography

powder particles

powder

powder

morphology

density


Input: Next, the same three powder lots were used to 3D-print and post-process a series of testing specimens with different layer thicknesses and build orientations, in order to establish a correlation between the powder characteristics and the geometric and mechanical properties of a final product.

powder

powder

post-process

mechanical properties

testing

layer thicknesses

build orientations


Input: This study demonstrates that the use of highly spherical powders with a limited amount of fine particles promotes their flowability and yields LPBF components with improved mechanical and geometric characteristics.

spherical

particles

powders

LPBF

components

mechanical


Input: Although the melt pool convection currents influence the dilution, porosity and distribution of potentially included hard phase particles such as carbide or other ceramic particles, which are added to increase the wear resistance of the deposited material, there is only limited knowledge of melt pool dynamics within blown powder additive manufacturing processes.

melt pool

as

ceramic

material

melt pool

powder

porosity

wear resistance

distribution

phase particles

additive manufacturing processes


Input: In the pursuit of a deeper understanding, a high-speed camera has been used to observe melt pool dynamics during laser cladding at a frame rate of up to 67’ 000 frames per second, allowing for the particles that swim on the surface to be traced automatically.

camera

melt pool

be

laser cladding

particles

surface


Input: The resulting videos allow for the melt pool surface behavior to be investigated using a specifically developed automated high-speed camera image evaluation technique.

melt pool

be

camera


Input: This method has been tested for reliability and applied to investigate the process parameter influence on melt pool dynamics.

reliability

process parameter

melt pool


Input: The results show, that there is no pronounced laminar flow on the melt pool surface, instead a remarkable randomness to the direction of particle flow can be observed.

melt pool

be

particle


Input: That being said, it is still possible to identify certain flow tendencies that can be explained by surface tension phenomena like the Marangoni effect and which depend on the process parameters.

be

surface tension

process parameters


Input: Laser Metal Deposition is a near-net-shape processing technology, which allows remarkable freedom in multi-material processing.

Laser Metal Deposition

near-net-shape

technology

multi-material


Input: It has been shown that multi-material processing of the two alloys via discrete as well as via gradual material transition is possible without any cracks for manufacturing small cubes.

multi-material

alloys

as

as

material

manufacturing


Input: Cross-sections of manufactured parts and tracks showed that a preheating temperature of at least 400 °C is necessary to process crack free samples.

Cross-sections

manufactured

process

samples

preheating


Input: EDX-analyses indicated that if a discrete material transition is required in multi-material processing, the material transition should be implemented in the vertical build-up direction because the mixing zone in this direction is significantly smaller than the mixing zone in the horizontal direction.

material

material

be

multi-material

vertical

mixing

mixing


Input: Due to the stronger mixing effects in the horizontal direction, a gradual material transition by a linear progression should be implemented in this direction rather than in the vertical direction.

mixing

vertical

material

be


Input: The mixing effects are mainly caused by melt flow, while diffusion effects can be neglected.

mixing

melt flow

diffusion

be


Input: Processing of the low workability Fe-Co-1.5V (Hiperco® equivalent) alloy is demonstrated using the Laser Engineered Net Shaping (LENS) metals additive manufacturing technique.

alloy

metals

Laser Engineered Net Shaping

LENS

additive manufacturing


Input: As an innovative and highly localized solidification process, LENS is shown to overcome workability issues that arise during conventional thermomechanical processing, enabling the production of bulk, near net-shape forms of the Fe-Co alloy.

As

alloy

solidification process

LENS

thermomechanical processing

production


Input: Bulk LENS structures appeared to be ductile with no significant macroscopic defects.

LENS

be

macroscopic defects


Input: Fine equiaxed grain structures were observed in as-built specimens following solidification, which then evolved toward a highly heterogeneous bimodal grain structure after annealing.

equiaxed grain

solidification

heterogeneous

grain structure

annealing


Input: The microstructure evolution in Fe-Co is discussed in the context of classical solidification theory and selective grain boundary pinning processes.

microstructure evolution

solidification

grain boundary

processes


Input: Magnetic properties were also assessed and shown to fall within the extremes of conventionally processed Hiperco® alloys.Hiperco® is a registered trademark of Carpenter Technologies, Readings, PA.

properties

processed

Technologies

PA


Input: The use of 3D printing in architecture has grown tremendously over the last decade thanks to its strong reputation as a versatile, cheap and fast technology.

3D printing

architecture

as

technology


Input: Its durability, in fact, depends on several factors (above all design accuracy, quality of materials and environmental aggressiveness), which may lead or contribute to rapid performance decay over time.

durability

design

accuracy

quality

materials

performance

lead


Input: With this in mind, the paper describes the design-to-production process for a façade shading system using additive manufacturing and the associated testing campaign to assess the feasibility of the design and durability of materials.

process

feasibility

materials

additive manufacturing

testing

design

durability


Input: Horizontal lamellas, with a complex curved geometry, were generated using computational design optimised for additive manufacturing.

geometry

design

additive manufacturing


Input: In order to select the most suitable 3D-printable material, tests were conducted on different polymers in a climatic chamber at Politecnico di Milano to monitor material performances over time at high temperatures such as the ones in Dubai.

material

polymers

material

as

monitor

temperatures


Input: The data gathered from these tests was crucial to the correct design of the façade manufacturing process.

data

design

manufacturing process


Input: Lattice structures are advantageous in terms of their high specific stiffness and strength, and have been applied to the design of lightweight structures owing to the recent development of additive manufacturing (AM).

Lattice structures

design

specific stiffness

strength

lightweight structures

additive manufacturing

AM


Input: The unique design flexibility of AM has enabled the fabrication of a functionally graded lattice (FGL) by gradually changing the lattice size and enhancing structural efficiency of lattice structures.

design flexibility

lattice

AM

fabrication

functionally graded lattice

lattice structures


Input: Although FGLs have been generally designed to reduce the compliance (i.e., to increase the stiffness), this study aims to develop soft polymeric lattices to widen the range of compliance for the development of FGLs.

designed

stiffness

lattices

range


Input: To develop soft lattice structures, various lattices were designed and fabricated using a photo-polymerization type 3D printer and photo-curable polyurethane resin.

lattice structures

designed

photo-curable

lattices

fabricated

3D printer

resin


Input: Compression tests were conducted on these lattices, and their deformation behaviors were analyzed experimentally.

Compression tests

lattices

deformation


Input: The effects of various lattice design parameters and the curing time were also investigated, and the resulting changes in the compliance were analyzed.

lattice design

curing time


Input: As a consequence, the compressive stiffness can vary widely, within a range of 10−3 to 102 N/mm.

As

stiffness

range


Input: Two types of FGLs, which enabled the self-positioning and self-guided moving functions, were then developed by varying the lattice direction, strut diameter and curing time effectively.

lattice

strut diameter

curing time


Input: The thermal conductivity of AlSi10Mg made by laser powder bed fusion (LPBF), and its modification via heat treatment, has received little attention despite possible applications for heat exchangers and thermo-mechanical components.

thermal conductivity

laser powder bed fusion

LPBF

heat treatment

heat exchangers

components

thermo-mechanical


Input: Here, we show that heat treatment can increase the thermal conductivity of LPBF AlSi10Mg to that of cast material.

heat treatment

LPBF

cast

thermal conductivity


Input: Our results indicate that post-manufacture annealing eliminates the thermal conductivity anisotropy present in the as-built condition, and enhances the conductivity by close to 30% in the transverse direction (perpendicular to the LPBF build orientation).

annealing

LPBF

thermal conductivity

anisotropy

conductivity

build orientation


Input: A solution heat treatment increases the thermal conductivity further still (36% compared to the as-built condition), while a T6-like treatment provides the greatest increase (44% compared to the as-built condition).

solution heat treatment

thermal conductivity


Input: These improvements are related to the evolution of the AlSi10Mg microstructure, especially the breakdown of the Si cellular structure.

evolution

Si

cellular structure


Input: Additionally, the thermal conductivities of gyroid lattice structures were examined in the as-built and annealed conditions.

thermal conductivities

lattice structures


Input: Contrary to solid specimens, the lattice structures exhibited almost isotropic thermal conductivity in the as-built condition.

lattice structures

isotropic

conductivity


Input: Their thermal conductivities were increased by the annealing treatment in proportion to their volume fraction.

thermal conductivities

annealing treatment

volume fraction


Input: Our findings contribute to the development of a general design-for-additive-manufacturing (DfAM) framework which will make the best possible use of AM materials and lattice structures for heat transfer components.

framework

heat transfer

AM materials

lattice structures

components


Input: Building on a large scale with Additive Manufacturing (AM) is one of the biggest manufacturing challenges of our time.

Additive Manufacturing

AM

manufacturing


Input: In the last decade, the proliferation of 3D printing has allowed architects and engineers to imagine and develop constructions that can be produced additively.

3D printing

be


Input: However, questions about the convenience of using this technology, and whether additive large-scale constructions can be feasible, efficient and sustainable are still open.

technology

sustainable

additive

be


Input: In this research 3D printing is considered not as a question, but as an answer to the increasing scarcity of material resources in the construction industry.

research

3D printing

as

as

material

construction


Input: This paper illustrates the overarching process from concept to the realisation of the Trabeculae Pavilion, a load-responsive architecture that is entirely designed and optimized for 3D printing, using Fused Filament Fabrication (FFF)-one of the most cost-effective additive techniques of production.

process

Trabeculae

additive

architecture

designed

3D printing

Fused Filament Fabrication

FFF

production


Input: The research methodology is based on a multi-scale computational workflow that integrates several aspects, such as material testing, bio-inspired design algorithms, multi-criteria optimization, and production management.

research methodology

workflow

bio-inspired design algorithms

optimization

as

testing

production


Input: The work culminates in the construction process of a full-scale architectural prototype; an anticlastic shell that features a cellular structure with increased material and structural efficiency.

construction

prototype

shell

cellular structure

material


Input: Microstructural characterization was carried out on AISI 17-4 PH stainless steel fabricated by selective laser melting (SLM) in an argon environment.

Microstructural characterization

17-4 PH stainless steel

argon

selective laser melting

SLM


Input: Conventionally, this steel exhibits a martensitic structure with a small fraction of δ ferrite.

steel

ferrite

structure

fraction


Input: However, the combined findings of x-ray diffraction and electron backscatter diffraction (EBSD) proved that SLM-ed 17-4 PH steel has a fully ferritic microstructure, more specifically δ ferrite.

x-ray diffraction

electron backscatter diffraction

EBSD

PH

ferritic

ferrite


Input: The microstructure consists of coarse ferritic grains elongated along the build direction, with a pronounced solidification crystallographic texture.

microstructure

solidification

ferritic

build direction

texture


Input: These results were associated to the high cooling and heating rates experienced throughout the SLM process that suppressed the austenite formation and produced a “by-passing” phenomenon of this phase during the numerous thermal cycles.

cooling

heating

SLM

process

phase

austenite

thermal cycles


Input: Furthermore, the energy-dispersive X-ray spectroscopy (EDS) measurements revealed a uniform distribution of elements without any dendritic structure.

X-ray

EDS

spectroscopy

distribution

structure

elements


Input: The extremely high cooling kinetics induced a diffusionless solidification, resulting in a homogeneous elemental composition.

cooling

solidification

homogeneous

composition


Input: It was also found that the ferritic SLM-ed material can be transformed to martensite again by re-austenitization at 1050 °C followed by quenching.

ferritic

material

be

martensite

quenching


Input: Electron Beam Melting (EBM) has the potentiality of being an effective system in terms of time and energy consumption.

Electron Beam Melting

EBM


Input: Among the different additive manufacturing processes that are available, the EBM process has shown the lowest Specific Energy Consumption (SEC) and the highest average Deposition Rate (DRa).

additive manufacturing processes

EBM

Specific Energy

average


Input: Moreover, all the literature studies have only an analysis of energy efficiency during the melting of the bulk material phase and have adopted a fixed job design.

melting

material

design


Input: A black-box approach is applied to provide a new model for the energy efficiency of the EBM process.

model

EBM


Input: Different jobs have been designed to analyse the effect of a part and of manufacturing designs.

designed

designs

manufacturing


Input: Bulk material, support and lattice structures have been included.

material

support

lattice structures


Input: The design has therefore been aimed at investigating the effect of the building height, melted area and process themes on energy efficiency.

design

melted

process

area


Input: The jobs have been produced using Arcam A2X and Standard Arcam Ti6Al4V powders.

Standard

Ti6Al4V powders


Input: According to this research, the architecture of the machine and its control of the process have the main impact on the relationship between SEC and DRa.

research

process

impact

architecture

machine


Input: Additionally, the empirical approach applied to the machine subunits has highlighted that only a small part of the total energy demand is needed to power the electron beam during the melting phase, while the remaining part guarantees the good machine working conditions.

empirical

electron beam

machine

machine

power

melting


Input: Laser powder bed fusion, is an additive manufacturing technology that is used in industry for rapid prototyping and manufacturing of aftermarket products, molds and special machine parts.

Laser powder bed fusion

additive manufacturing

manufacturing

industry

rapid prototyping

molds

machine


Input: Quality assurance and process stability still require improvement until this technology is ready for large scale serial production.

Quality

process

technology

production


Input: Scan strategies and parameter sets for manufacturing are often fixed when certification processes are finished.

parameter

processes

manufacturing


Input: Thus, it is important to test the manufacturability of specific design features such as inner channels.

manufacturability

design

as


Input: In the following we will present the qualification of inner channels in different test parts for the aluminum alloy AlSi10Mg and the stainless steel 1.4542.

aluminum alloy

stainless steel


Input: The testing includes different cleaning methods and air flow rate measurements.

testing

cleaning

flow rate


Input: Additionally, we will compare such parts and LPBF specific problems to observations with a coaxial melt pool monitoring system.

LPBF

melt pool


Input: A system for the additive manufacturing of functionally graded concrete parts was developed.

additive manufacturing

functionally graded concrete


Input: It is possible to 3D print functionally graded concrete parts by varying the type and ratio of aggregates.

3D print

concrete

aggregates


Input: Homogeneous and functionally graded parts were produced with the system.

Homogeneous

functionally graded


Input: Cork is a viable natural aggregate for concrete printing.

Cork

natural aggregate

concrete printing


Input: In recent years, the interest in developing additive manufacturing (AM) technologies in the architecture, engineering and construction (AEC) industry has increased, motivated by the potential to support greater formal complexity.

additive manufacturing

AM

technologies

complexity

architecture

engineering

construction

AEC

industry

support


Input: In this context, AM has been largely used to design and fabricate physical parts with homogeneous materials.

AM

fabricate

design

homogeneous materials


Input: This paper proposes a new strategy, aimed at the design and fabrication of functionally graded concrete parts with specific thermo-mechanical performance.

design

fabrication

functionally graded concrete

thermo-mechanical performance


Input: The paper describes the development of the AM system to materialize such parts.

AM

materialize


Input: The computational tool developed to design the material to meet specific performance requirements, and the design and testing of the material are described elsewhere.

computational tool

performance

design

design

material

material

testing


Input: A functionally graded concrete part obtained by replacing sand with cork was produced and is evaluated.

functionally graded concrete

sand

cork


Input: Mechanical properties (tensile strength and creep) of AlSi10Mg specimens fabricated by selective laser melting (SLM) in the Z-direction were investigated in the 25–400 °C temperature range.

Mechanical properties

fabricated

tensile strength

creep

selective laser melting

SLM

Z-direction

temperature range


Input: Specimens were tested after stress relief treatment.

stress


Input: The results revealed that yield stress (YS) significantly decreases and the elongation increases at temperatures higher than 200 °C.

yield stress

elongation

temperatures


Input: The ultimate tensile stress (UTS) continuously decreases with temperature.

tensile stress

UTS

temperature


Input: The creep parameters, namely stress exponent n and apparent activation energy Q, were found to be 25 ± 2 and 146 ± 20 kJ/mole, respectively.

creep

stress

n

be


Input: It was shown that plastic deformation during creep is governed by dislocation movements in primary aluminum grains.

plastic deformation

creep

dislocation

aluminum


Input: The tested material is actually an aluminum composite reinforced by sub-micron Si particles.

material

aluminum

Si

reinforced

particles

sub-micron


Input: The creep resistance of AlSi10Mg alloy fabricated by selective laser melting is close to that for aluminum matrix particles reinforced composites.

creep

AlSi10Mg alloy

aluminum

composites

selective laser melting

particles


Input: Recyclability of Ti-6Al-4 V powder by EBM process has been investigated.

Recyclability

Ti-6Al-4 V powder

EBM


Input: The effect of powder recycling was explored using metallographic and mechanical testing.

powder

mechanical testing


Input: Recycling causes various defects to appear in Ti-6Al-4 V powder, having a negative effect on the EBM process.

Recycling

defects

Ti-6Al-4 V powder

EBM


Input: HIP significantly improves the quality of the samples made from recycled powder.

HIP

quality

samples

recycled

powder


Input: Additive manufacturing (AM), also called 3D-printing, is an innovative technology, as the printing of objects is performed by layer-by-layer deposition.

Additive manufacturing

AM

technology

layer-by-layer deposition

as


Input: A wide variety of materials can be used to produce a variety of shapes that can not be achieved using any other technology.

materials

technology

be

be


Input: AM started as a prototyping in plastics, and now it is successfully implemented with metals.

AM

as

plastics

metals

prototyping


Input: AM in metals, first of all, in Titanium alloys, offers the potential to not only generate net-shape, complex geometrical and light-weight objects, but also to achieve enhanced mechanical properties, even better than achieved by traditional mass production, like casting.However, the priority of achieving good non-porous microstructure and the desired mechanical properties is a challenge for the main fields of applications of Titanium AM, such as the aerospace industry and production of medical implants.

AM

AM

production

metals

Titanium alloys

Titanium

as

light-weight

mechanical properties

mass production

microstructure

mechanical properties

aerospace industry

medical implants


Input: Thus, the quality of the powder and standardization of the AM process are the top priority.

quality

powder

AM process


Input: The potential recycling of the Ti-6Al-4 V powder as an inextricable part of the AM process needs to be explored.The influence of powder recycling on Ti-6Al-4 V additive manufacturing, the correct number of cycles, the requirements of the recycling procedures, and possible post processing procedures–are still open questions.

recycling

recycling

post processing

Ti-6Al-4 V powder

as

be

powder

Ti-6Al-4 V

AM process

additive manufacturing


Input: This research aims to answer these questions.

research


Input: Two identical test cylinder sets were printed, one from recycled powder and one from the new powder batch.

recycled

powder

powder


Input: The cylinders were printed by the Arcam EBM A2X machine using a start platform of 210 x 210 mm in size.

EBM

mm

machine

platform


Input: Electron Beam Melting (EBM) is a well-known effective manufacturing process.

Electron Beam Melting

EBM

manufacturing process


Input: This AM technology utilizes high power electron beam to produce layer-by-layer metal parts for various applications, such as fabrication of biomedical implants and aerospace components.

AM technology

power

electron beam

layer-by-layer

as

biomedical

aerospace components


Input: The microstructure and mechanical properties of the printed specimens from the two sets (new and recycled Ti-6Al-4 V powder) were investigated before and after heat treatment.

microstructure

mechanical properties

recycled

V

powder

heat treatment


Input: A novel approach to fabricate ceramic structures at multiple scales in a single component, based on the hybridization of additive manufacturing technologies, was developed by combining 3D macro-stereolithography (Digital Light Processing, DLP) with two-photon lithography (2PL), to produce cm-sized sample geometries with sub-μm surface features.

fabricate

additive manufacturing

Digital Light Processing

DLP

ceramic

component

lithography

sample

geometries

surface


Input: The preceramic structures in the sub-μm scale were realized by 2PL directly on easily manageable DLP macro-sized samples of the same ceramic composition.

DLP

samples

ceramic


Input: In this way, preceramic structures presenting both features typical of DLP printers (with a minimum size of around 50 μm) and features well below their resolution limit were realized.

DLP printers

resolution

limit


Input: We report here, for the first time, the realization of polymer-derived ceramic SiOC ceramic components structured in 3D across several length scales (with micron and mesoscale 3D features), produced by pyrolysis at 1000 °C of preceramic parts, without shape distortion during the pyrolysis step.

ceramic

ceramic

mesoscale 3D

distortion

length scales

micron

pyrolysis

pyrolysis


Input: The effect of varying the solids volume fraction of an aqueous clay paste suspension on its printability via an Additive Manufacturing (AM) or 3D printing technique, Direct Ink Writing (DIW) or material extrusion, has been studied.

volume fraction

printability

clay

Ink

Additive Manufacturing

AM

3D printing

DIW

material extrusion


Input: DIW is a cost-effective and straightforward fabrication technology suitable for adoption at a larger-scale by the traditional ceramics industry and the creative community.

DIW

fabrication

traditional ceramics

industry


Input: The pastes were prepared with volume fraction of solids ranging from 25 to 57 vol%.

volume fraction


Input: Their rheological properties (storage modulus and apparent yield stress) were measured by dynamic oscillatory rheometry.

rheological properties

yield stress

dynamic


Input: The relationships between solids content, rheological behaviour and print parameters were evaluated.

rheological

print

parameters


Input: An equation based on rheological properties to delineate between printable and non-printable conditions has been proposed.

rheological properties


Input: In this study, we present the first results of a newly developed melt pool monitoring tool for selective laser melting, called DMP-meltpool.

melt pool

tool

selective laser melting


Input: A manual data analysis method is given, and the events indicated by the analysis (DMP-meltpool events) are shown to correlate to the static tensile properties of the samples built.

data

samples

tensile properties


Input: These events indicate the probability of material discontinuities (defects) in the metal additive manufacturing (AM) parts.

probability

defects

material

metal additive manufacturing

AM


Input: In order to do so, cylindrical bars of Ti-6Al-4V ELI were built and monitored using DMP-meltpool.

cylindrical


Input: The tensile properties of the printed cylinders were correlated with the events detected by DMP-meltpool.

tensile properties

correlated


Input: An inverse relation between plastic elongation and the DMP-meltpool event density was observed.

plastic

elongation

density


Input: These results show that DMP-meltpool can be used to predict the quality of AM parts by detecting variations in the signals and tagging these events throughout the build as defects.

be

as

quality

variations

AM parts

build


Input: Thus the technique can be employed for first stage in-line quality control of AM parts and for sorting out parts with potential defects non-destructively.

be

quality control

defects

AM parts


Input: The DMP-meltpool events could have significant correlations with other mechanical properties (like fatigue, hardness, fracture toughness, and crack propagation) since such properties are influenced by defects originating from the process instabilities.

mechanical properties

fracture

crack propagation

properties

defects

process

fatigue

hardness


Input: This study compares the mechanical response and microstructure of Co–Cr–Mo removable partial denture models made through conventional lost-wax casting and the selective laser melting additive manufacturing process.

mechanical response

microstructure

denture

casting

selective laser melting

additive manufacturing process


Input: Co–Cr–Mo clasps for removal partial dentures, based on a wax model (BEGO USA), were fabricated through lost-wax technique and selective laser melting, and subjected to mechanical bending experiments to determine their yield strength and maximum reversible deformation.

dentures

mechanical

wax

model

fabricated

deformation

selective laser melting

bending

yield strength


Input: Microstructure and chemical composition of the clasps were determined through scanning electron microscopy and wave-dispersive spectroscopy to rationalize the differences and similarities in the mechanical testing results from the two groups.It was found that the clasps made using lost-wax technique and selective laser melting exhibit comparable mean yield strengths and maximum elastic deformations, however the underlying microstructure of the cast clasps vastly differs from the laser-melted counterparts.

Microstructure

chemical composition

spectroscopy

microstructure

scanning electron microscopy

mechanical testing

selective laser melting

cast

yield strengths

elastic deformations


Input: Furthermore, the laser melted clasps exhibit larger variability in their mechanical response.

laser

variability

mechanical response


Input: While selective laser melting is capable of producing removable partial denture clasps with similar average mechanical responses to those of lost-wax cast counterparts, additional studies should be conducted to minimize the variability in the laser melted clasps in order to minimize unexpected failures.

selective laser melting

cast

denture

average

variability

be

laser


Input: Optical Emissions Spectroscopy and plume imaging were utilized to investigate flaws generated during directed energy deposition additive manufacturing.

Optical

Spectroscopy

flaws

imaging

directed energy deposition additive manufacturing


Input: Ti-6Al–4 V coupons were built using varying laser power, powder flow rate, and hatching pattern to induce random and systematic flaws.

V

laser power

powder flow rate

pattern

flaws


Input: X-Ray Computed Tomography (CT) scans were completed on each part to determine flaw density and flaw locations.

X-Ray Computed Tomography

CT

flaw

flaw

density


Input: For coupons built with constant laser power, variations in either powder flow rate or hatch pattern that led to an increase in flaw density were accompanied by an increase in median line-to-continuum ratios around 430 and 520 nm and in total plume area.

laser power

powder flow rate

area

variations

pattern

flaw

led

density


Input: These results present a path forward for real-time flaw detection and assessment of build quality in directed energy deposition and powder bed fusion processes.

flaw detection

build

directed energy deposition

powder bed fusion processes


Input: This study examines the impact of low-temperature heat-treatment on the microstructure and corrosion performance of direct metal laser sintered (DMLS) -AlSi10Mg alloy.

impact

microstructure

corrosion

direct metal laser

DMLS

alloy


Input: Differential scanning calorimetry (DSC) was used to determine the phase (s) transition temperatures in the alloy.

scanning

phase

transition

DSC

s

alloy

temperatures


Input: Two exothermic phenomena were detected and associated with the Mg2Si precipitation and Si phase precipitation in the as-printed alloy.

Si

alloy

phase


Input: Based on DSC results, thermal-treatments including below and above the active Si precipitation temperature at 200 °C and 300 °C, respectively, and 350 °C as an upper limit temperature for 3 h were applied to the as-printed samples.

DSC

Si

as

precipitation

limit

samples


Input: Scanning electron microscopy and X-ray diffraction analysis confirmed that heat-treatment from 200 °C to 350 °C promotes the homogeneity of the microstructure, characterized by uniform distribution of eutectic Si in α-Al matrix.

Scanning electron microscopy

X-ray diffraction analysis

microstructure

distribution

eutectic


Input: To investigate the impact of the applied heat-treatment cycles on corrosion resistance of DMLS-AlSi10Mg at early stage of immersion, anodic polarization testing and electrochemical impedance spectroscopy were performed in aerated 3.5 wt.% NaCl solution.

impact

corrosion resistance

electrochemical

spectroscopy

testing

NaCl


Input: The results revealed more uniformly distributed pitting attack on the corroded surfaces by increasing the heat-treatment temperature up to 300 °C, attributed to the more protective nature of the spontaneously air-formed passive layer on the surface of the alloy at initial immersion time.

pitting

surfaces

surface

temperature

layer

alloy


Input: Further increase of the heat treatment temperature to 350 °C induced severe localized corrosion attacks near the coarse Si particles, ascribed to the increased potential difference between the coalesced Si particles and aluminum matrix galvanic couple.

heat treatment

corrosion

particles

particles

Si

Si

aluminum


Input: In comparison, the corrosion of the as-printed and 200 °C heat treated samples was characterized by a penetrating selective attack along the melt pool boundaries, leading to a higher corrosion current density and an active surface at early exposure, associated with the weakness of the existing passive film on their surfaces.

corrosion

heat

samples

melt pool boundaries

corrosion

surface

exposure

surfaces

density


Input: A testing methodology was developed to expose photopolymer resins and measure the cured material to determine two key parameters related to the photopolymerization process: Ec (critical energy to initiate polymerization) and Dp (penetration depth of curing light).

testing

methodology

parameters

photopolymer resins

cured

photopolymerization

polymerization

curing

penetration depth


Input: Five commercially available resins were evaluated under exposure from 365 nm and 405 nm light at varying power densities and energies.

resins

exposure

power


Input: Caliper measurements, stylus profilometry, and confocal laser scanning microscopy showed similar results for hard materials while caliper measurement of a soft, elastomeric material proved inaccurate.

Caliper

stylus

caliper

laser

microscopy

materials

material


Input: Working curves for the five photopolymers showed unique behavior both within and among the resins as a function of curing light wavelength.

photopolymers

resins

as

curing

wavelength


Input: Ec and Dp for the five resins showed variations as large as 10x.

resins

as

as

variations


Input: Variations of this magnitude, if unknown to the user and not controlled for, will clearly affect printed part quality.

Variations

quality

magnitude


Input: Rapid prototyping of smart objects with embedded electronics.

Rapid prototyping

embedded electronics


Input: Integrated additive manufacturing approach.

additive manufacturing


Input: Polymer/metal nanocomposite conductive lines with controlled electrical properties.

electrical properties


Input: Fabrication of conductive 3D oblique paths, bridging vias and standard sockets.

Fabrication

bridging

standard


Input: Freeform monolithic smart nightlight sensor.

Freeform

sensor


Input: We present an integrated additive manufacturing approach for the rapid prototyping of objects with embedded electric circuits.

additive manufacturing

rapid prototyping


Input: Our approach relies on the combined use of standard fused filament fabrication (FFF) for the production of thermoplastic 3D freeform components, and supersonic cluster beam deposition (SCBD) for the fabrication of embedded electrical conducting lines and resistors with tailored conductivity.

standard

fused filament fabrication

FFF

production

fabrication

thermoplastic

components

resistors

beam deposition

electrical

conductivity


Input: SCBD is an additive fabrication technique based on the deposition of neutral metallic clusters carried in a highly collimated supersonic beam.

additive

metallic

deposition

beam


Input: A multi-step fabrication procedure alternating FFF and SCBD was developed and optimized allowing the fabrication of conductive 3D oblique paths, bridging vias, and sockets for standard electronic components fitting.

fabrication

FFF

fabrication

bridging

standard

components


Input: This resulted in the simplification of the topology of planar electric circuits by enabling out-of-plane connections, minimizing the implementation of bulky passive electrical components and avoiding the use of soldering and conductive adhesives for the integration of active electronic components.

topology

electrical

components

components

soldering

adhesives


Input: A dark-activated light sensor was produced as a demonstrator.

sensor

as


Input: Polyolefin thermoplastics like high density polyethylene (HDPE) are the leaders in terms of world-scale plastics’ production, environmentally benign polymerization processes, recycling, and sustainability.

Polyolefin thermoplastics

high density polyethylene

HDPE

plastics

production

polymerization

recycling

sustainability


Input: However, additive manufacturing of HDPE by means of fused deposition modeling (FDM) also known as fused filament fabrication (FFF) has been problematic owing to its massive shrinkage, voiding and warpage problems accompanied by its poor adhesion to common build plates and to extruded HDPE strands.

additive manufacturing

fused deposition modeling

FDM

fabrication

FFF

extruded

HDPE

as

filament

shrinkage

voiding

warpage

adhesion

build plates


Input: Herein we overcome these problems and improve Young’ s modulus, tensile strength and surface quality of 3D printed HDPE by varying 3D printing parameters like temperature and diameter of the nozzle, extrusion rate, build plate temperature, and build plate material.

s

tensile strength

surface quality

temperature

extrusion rate

3D printed

3D printing

diameter

build plate material

nozzle

build plate


Input: Both nozzle diameter and printing speed affect surface quality but do not impair mechanical properties.

nozzle diameter

mechanical properties

printing speed

surface quality


Input: Particularly, an extrusion rate gradient prevents void formation.

extrusion rate gradient

void


Input: For the first time additive manufactured HDPE and injection-molded HDPE exhibit similar mechanical properties with exception of elongation at break.

additive manufactured

HDPE

mechanical properties

elongation


Input: Excellent fusion of the extruded polymer strands and the absence of anisotropy are achieved, as verified by microscopic imaging and measuring the tensile strength parallel and perpendicular to the 3D printing direction.

fusion

microscopic imaging

extruded

3D printing

anisotropy

tensile strength

as


Input: Refractory elements have high melting points and are difficult to melt and cast.

Refractory

elements

melting points

melt

cast


Input: In this study it is successfully demonstrated for the first time that laser metal deposition can be used to produce TiZrNbHfTa high-entropy alloy from a blend of elemental powders by in-situ alloying.

laser metal deposition

be

alloy

blend

powders

in-situ

alloying


Input: Columnar specimens with a height of 10 mm and a diameter of 3 mm were deposited with a pulsed Nd: YAG laser.

mm

mm

diameter

Nd: YAG

laser


Input: The built-up specimen has near-equiatomic composition, nearly uniform grain size, equiaxed grain shape, is bcc single phase and exhibits a high hardness of 509 HV0.2.

composition

equiaxed grain

bcc

phase

grain size

hardness


Input: Material properties of parts made via selective laser melting are not the same as the well-established properties for bulk base materials, due to the unique processes used to produce the parts.

Material properties

properties

materials

processes

selective laser melting

as


Input: Meanwhile, additive manufacturing is increasingly being used for heat exchangers and heat removal devices, which demand high thermal conductivities.

additive manufacturing

heat exchangers

heat

thermal conductivities


Input: The thermal properties are also important for many non-destructive testing technologies.

thermal properties

non-destructive testing


Input: The thermal conductivity of selective laser melted 316 L stainless steel was studied as a function of processing conditions and build orientation.

thermal conductivity

selective laser melted

stainless steel

as

build orientation


Input: The porosity and thermal conductivity were measured versus processing conditions.

porosity

thermal conductivity


Input: A critical energy density of 44.4 J/mm3 was observed below which the porosity increased and the thermal conductivity decreased.

energy density

porosity

thermal conductivity


Input: For the lowest-porosity sample, the local thermal conductivity map taken with frequency domain thermoreflectance showed a variation in the stainless steel thermal conductivity between 10.4 and 19.8 W/m-K, while the average thermal conductivity of 14.3 W/m-K from the thermal conductivity map agreed, within measurement uncertainty, with the bulk thermal conductivity measurements.

sample

domain

variation

average

thermal conductivity

conductivity

conductivity

thermal conductivity

thermal conductivity

stainless steel

measurement


Input: The thermal conductivity trend was not fully explained by the porosity, as effective medium models fail to predict the trend.

thermal conductivity

porosity

as

trend


Input: Amorphous stripes in the selective laser melted stainless steel grains were identified by transmission electron microscopy.

selective laser melted

steel

grains

transmission electron microscopy


Input: These amorphous regions also resulted in decreased x-ray diffraction intensities with increasing porosity.

x-ray diffraction

porosity


Input: The amorphous regions are hypothesized to lower the thermal conductivity at faster laser scanning speeds due to less time at elevated temperatures.

thermal conductivity

laser

temperatures


Input: We also found that in-print plane and through-print plane thermal conductivities have the same value when the energy density is greater than this critical amount.

thermal conductivities

energy density


Input: When the energy density reduces below this critical amount, the in-plane conductivity exceeds the through-plane.

energy density

conductivity


Input: Inconel 718 alloy rods were fabricated by electron–beam melting (EBM), where the cylindrical axes (CAs) deviated from the build directions (BD) by 0°, 45°, 55°, and 90°.

Inconel 718 alloy

fabricated

cylindrical

melting

EBM

build directions