The Experts below are selected from a list of 96333 Experts worldwide ranked by ideXlab platform
Kevin Chou - One of the best experts on this subject based on the ideXlab platform.
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Phase-field simulation of microstructure evolution of Ti-6Al-4V in electron beam additive manufacturing process
Additive Manufacturing, 2016Co-Authors: Seshadev Sahoo, Kevin ChouAbstract:Electron beam additive manufacturing (EBAM) is a relatively new technology to produce metallic parts in a layer by layer fashion by melting and fusing the metallic powders. Ti-6Al-4V is one of the most used industrial alloys used for aerospace and biomedical application. EBAM is a rapid solidification process and the properties of the Build Material depend on the solidification behavior as well as the microstructure of the Build Material. Thus, the prediction of part microstructures during the process may be an important factor for process optimization. In this study, a phase field model is developed for microstructure evolution of Ti-6Al-4V powder in EBAM process. FORTRAN code is used to solve the phase field equations, which incorporates the temperature gradient and solidification velocity as the simulation parameters. The effect of temperature gradient and the beam scan speed on microstructure is investigated through simulation. The simulation results are compared with the analytical model and experimental findings by measuring the spacing evolution under the solidification condition.
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phase field modeling of microstructure evolution in electron beam additive manufacturing
JOM, 2015Co-Authors: Xibing Gong, Kevin ChouAbstract:In this study, the microstructure evolution in the powder-bed electron beam additive manufacturing (EBAM) process is studied using phase-field modeling. In essence, EBAM involves a rapid solidification process and the properties of a Build partly depend on the solidification behavior as well as the microstructure of the Build Material. Thus, the prediction of microstructure evolution in EBAM is of importance for its process optimization. Phase-field modeling was applied to study the microstructure evolution and solute concentration of the Ti-6Al-4V alloy in the EBAM process. The effect of undercooling was investigated through the simulations; the greater the undercooling, the faster the dendrite grows. The microstructure simulations show multiple columnar-grain growths, comparable with experimental results for the tested range.
Ross J. Friel - One of the best experts on this subject based on the ideXlab platform.
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mechanical behaviour of additively manufactured lunar regolith simulant components
Proceedings of the Institution of Mechanical Engineers Part L: Journal of Materials: Design and Applications, 2019Co-Authors: Athanasios Goulas, Daniel S. Engstrøm, Ross J. FrielAbstract:Additive manufacturing and its related techniques have frequently been put forward as a promising candidate for planetary in-situ manufacturing, from Building life-sustaining habitats on the Moon to fabricating various replacements parts, aiming to support future extra-terrestrial human activity. This paper investigates the mechanical behaviour of lunar regolith simulant Material components, which is a potential future space engineering Material, manufactured by a laser-based powder bed fusion additive manufacturing system. The influence of laser energy input during processing was associated with the evolution of component porosity, measured via optical and scanning electron microscopy in combination with gas expansion pycnometry. The compressive strength performance and Vickers micro-hardness of the components were analysed and related back to the processing history and resultant microstructure of the lunar regolith simulant Build Material. Fabricated structures exhibited a relative porosity of 44–49% and densities ranging from 1.76 to 2.3 g cm−3, with a maximum compressive strength of 4.2 ± 0.1 MPa and elastic modulus of 287.3 ± 6.6 MPa, the former is comparable to a typical masonry clay brick (3.5 MPa). The additive manufacturing parts also had an average hardness value of 657 ± 14 HV0.05/15, better than borosilicate glass (580 HV). This study has shed significant insight into realising the potential of a laser-based powder bed fusion additive manufacturing process to deliver functional engineering assets via in-situ and abundant Material sources that can be potentially used for future engineering applications in aerospace and astronautics. (Less)
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Mechanical behaviour of additively manufactured lunar regolith simulant components
2019Co-Authors: Athanasios Goulas, J.g.p. Binner, Daniel Engstrom, Russell A. Harris, Ross J. FrielAbstract:Additive manufacturing and its related techniques have frequently been put forward as a promising candidate for planetary in-situ manufacturing, from Building life-sustaining habitats on the Moon to fabricating various replacements parts, aiming to support future extra-terrestrial human activity. This paper investigates the mechanical behaviour of lunar regolith simulant Material components, which is a potential future space engineering Material, manufactured by a laser-based powder bed fusion additive manufacturing system. The influence of laser energy input during processing was associated with the evolution of component porosity, measured via optical and scanning electron microscopy in combination with gas expansion pycnometry. The compressive strength performance and Vickers microhardness of the components were analysed and related back to the processing history and resultant microstructure of the lunar regolith simulant Build Material. Fabricated structures exhibited a relative porosity of 44 – 49% and densities ranging from 1.76 – 2.3 g cm-3, with a maximum compressive strength of 4.2 ± 0.1 MPa and elastic modulus of 287.3 ± 6.6 MPa, the former is comparable to a typical masonry clay brick (3.5 MPa). The 2AM parts also had an average hardness value of 657 ± 14 HV0.05/15, better than borosilicate glass (580 HV). This study has shed significant insight into realizing the potential of a laser-based powder bed fusion AM process to deliver functional engineering assets via in-situ and abundant Material sources that can be potentially used for future engineering applications in aerospace and astronautics
Friel, Ross J. - One of the best experts on this subject based on the ideXlab platform.
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Mechanical behaviour of additively manufactured lunar regolith simulant components
'SAGE Publications', 2019Co-Authors: Goulas Athanasios, Binner, Jon G.p., Engstrøm, Daniel S., Harris, Russell A., Friel, Ross J.Abstract:Additive manufacturing and its related techniques have frequently been put forward as a promising candidate for planetary in-situ manufacturing, from Building life-sustaining habitats on the Moon to fabricating various replacements parts, aiming to support future extra-terrestrial human activity. This paper investigates the mechanical behaviour of lunar regolith simulant Material components, which is a potential future space engineering Material, manufactured by a laser-based powder bed fusion additive manufacturing system. The influence of laser energy input during processing was associated with the evolution of component porosity, measured via optical and scanning electron microscopy in combination with gas expansion pycnometry. The compressive strength performance and Vickers micro-hardness of the components were analysed and related back to the processing history and resultant microstructure of the lunar regolith simulant Build Material. Fabricated structures exhibited a relative porosity of 44–49% and densities ranging from 1.76 to 2.3 g cm−3, with a maximum compressive strength of 4.2 ± 0.1 MPa and elastic modulus of 287.3 ± 6.6 MPa, the former is comparable to a typical masonry clay brick (3.5 MPa). The additive manufacturing parts also had an average hardness value of 657 ± 14 HV0.05/15, better than borosilicate glass (580 HV). This study has shed significant insight into realising the potential of a laser-based powder bed fusion additive manufacturing process to deliver functional engineering assets via in-situ and abundant Material sources that can be potentially used for future engineering applications in aerospace and astronautics
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Mechanical behaviour of additively manufactured lunar regolith simulant components
'SAGE Publications', 2019Co-Authors: Goulas Athanasios, Engstrøm, Daniel S., Harris, Russell A., J.g.p. Binner, Friel, Ross J.Abstract:Additive manufacturing and its related techniques have frequently been put forward as a promising candidate for planetary in-situ manufacturing, from Building life-sustaining habitats on the Moon to fabricating various replacements parts, aiming to support future extra-terrestrial human activity. This paper investigates the mechanical behaviour of lunar regolith simulant Material components, which is a potential future space engineering Material, manufactured by a laser-based powder bed fusion additive manufacturing system. The influence of laser energy input during processing was associated with the evolution of component porosity, measured via optical and scanning electron microscopy in combination with gas expansion pycnometry. The compressive strength performance and Vickers micro-hardness of the components were analysed and related back to the processing history and resultant microstructure of the lunar regolith simulant Build Material. Fabricated structures exhibited a relative porosity of 44–49% and densities ranging from 1.76 to 2.3 g cm−3, with a maximum compressive strength of 4.2 ± 0.1 MPa and elastic modulus of 287.3 ± 6.6 MPa, the former is comparable to a typical masonry clay brick (3.5 MPa). The additive manufacturing parts also had an average hardness value of 657 ± 14 HV0.05/15, better than borosilicate glass (580 HV). This study has shed significant insight into realising the potential of a laser-based powder bed fusion additive manufacturing process to deliver functional engineering assets via in-situ and abundant Material sources that can be potentially used for future engineering applications in aerospace and astronautics. © 2018, IMechE 2018
Lin Li - One of the best experts on this subject based on the ideXlab platform.
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Modelling powder concentration distribution from a coaxial deposition nozzle for laser-based rapid tooling
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2004Co-Authors: Andrew J. Pinkerton, Lin LiAbstract:Direct laser deposition is a solid freeform fabrication process that is capable of producing fully dense components with full structural integrity and is greatly enhanced by. the use of an onmidirectional coaxial powder nozzle to supply the Build Material. In order to optimize the technique, accurate control of the two critical operational parameters of Material feed rate and incident laser power intensity is necessary. Both parameters are affected by the axial powder stream concentration between the nozzle and the deposition point. In this work, a mathematical model for the powder concentration distribution is developed and the results from it compared with an experimental investigation using optical and image analysis techniques. The two show good agreement. The application of the model to the evaluation of nozzle geometry and the calculation of laser beam attenuation are demonstrated.
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An investigation of the effect of pulse frequency in laser multiple-layer cladding of stainless steel
Applied Surface Science, 2003Co-Authors: Andrew J. Pinkerton, Lin LiAbstract:The consolidation of metal powder onto a solid substrate using a laser beam allows fusion of the Build Material to be realised and fully-dense walls or surfaces, suitable for rapid prototyping and tooling applications, to be fabricated. The final wall geometry and microstructure of metals deposited in this way are determined in part by the pulse frequency of the laser beam used. A 1.2 kW CO2 laser, operating over a range of different pulse frequencies is used to investigate this effect. Microstructural characterisation of multiple layers of consolidated 316L steel revealed a coarser, but less porous austenitic structure when using a pulsed beam. The final hardness of the steel increased with pulse frequency, but was not constant throughout the wall, and the surface roughness varied little.
Seshadev Sahoo - One of the best experts on this subject based on the ideXlab platform.
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Phase-field simulation of microstructure evolution of Ti-6Al-4V in electron beam additive manufacturing process
Additive Manufacturing, 2016Co-Authors: Seshadev Sahoo, Kevin ChouAbstract:Electron beam additive manufacturing (EBAM) is a relatively new technology to produce metallic parts in a layer by layer fashion by melting and fusing the metallic powders. Ti-6Al-4V is one of the most used industrial alloys used for aerospace and biomedical application. EBAM is a rapid solidification process and the properties of the Build Material depend on the solidification behavior as well as the microstructure of the Build Material. Thus, the prediction of part microstructures during the process may be an important factor for process optimization. In this study, a phase field model is developed for microstructure evolution of Ti-6Al-4V powder in EBAM process. FORTRAN code is used to solve the phase field equations, which incorporates the temperature gradient and solidification velocity as the simulation parameters. The effect of temperature gradient and the beam scan speed on microstructure is investigated through simulation. The simulation results are compared with the analytical model and experimental findings by measuring the spacing evolution under the solidification condition.
