The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Yan Ying Du - One of the best experts on this subject based on the ideXlab platform.
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forming simulation and experimental verification of combined formation of selective laser sintering and cold Isostatic Pressing
Journal of Materials Engineering and Performance, 2011Co-Authors: Yan Ying DuAbstract:Selective laser sintering (SLS) could manufacture complex parts rapidly which, however, have high porosity and low intensity. While the parts made by cold Isostatic Pressing have advantages of uniform structure without composition segregation, high-dimension precision and high density. However, it could not form high complex parts because of the difficulties in manufacturing bag. A combination of SLS and cold Isostatic Pressing is expected to use the advantages of the two methods and is an efficient way to make complicated parts rapidly. After SLS and cold Isostatic Pressing, dimensions of parts decrease and relative density increases. To predict final dimensions and density, the finite element simulations are performed for cold Isostatic Pressing. The results show the parts made from ball shape powder contract symmetrically. The simulation results agree with the achieved geometries within 4%. Comparisons are made with that parts made from irregular powder. The SEM pictures after SLS are also showed. This has an important indication to process of SLS and cold Isostatic Pressing forming.
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forming simulation and experimental verification of combined formation of selective laser sintering and cold Isostatic Pressing
Journal of Materials Engineering and Performance, 2011Co-Authors: Yan Ying DuAbstract:Selective laser sintering (SLS) could manufacture complex parts rapidly which, however, have high porosity and low intensity. While the parts made by cold Isostatic Pressing have advantages of uniform structure without composition segregation, high-dimension precision and high density. However, it could not form high complex parts because of the difficulties in manufacturing bag. A combination of SLS and cold Isostatic Pressing is expected to use the advantages of the two methods and is an efficient way to make complicated parts rapidly. After SLS and cold Isostatic Pressing, dimensions of parts decrease and relative density increases. To predict final dimensions and density, the finite element simulations are performed for cold Isostatic Pressing. The results show the parts made from ball shape powder contract symmetrically. The simulation results agree with the achieved geometries within 4%. Comparisons are made with that parts made from irregular powder. The SEM pictures after SLS are also showed. This has an important indication to process of SLS and cold Isostatic Pressing forming.
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finite element simulation of cold Isostatic Pressing of the selective laser sintered components
Materials and Manufacturing Processes, 2010Co-Authors: Yan Ying DuAbstract:The article discusses the simulation of forming process of cold Isostatic Pressing of the selective laser-sintered components. A cylindrical specimen and a turbine component made of stainless steel powder were fabricated by this forming route. In order to achieve the purpose of the near net shape, the simulations of cold Isostatic pressure were carried out. The simulations were based on the Drucker-Prager-Cap constitutive model. The properties of the metallic powder were measured by the experiments. The effect of a rubber bag on cold Isostatic Pressing is discussed. The results show that a rubber bag has little influence on both shape and size of the specimen. The results of the simulations show good agreement between the experimental results and the calculated results. The simulations can give a useful direction to the design of dimensions of the combined forming process of selective laser sintering and cold Isostatic Pressing.
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finite element simulation of combined forming of selective laser sintering and cold Isostatic Pressing
Applied Mechanics and Materials, 2010Co-Authors: Yan Ying DuAbstract:Selective Laser Sintering could manufacture high complex metal parts in short time but with high porosity and low strength. The components from Cold Isostatic Pressing have excellent performance with uniform organizational structure, high size precision, and high density. It, however, could not form high complex parts because of the difficulties of bag manufacture. So it will be a good method to combine Selective Laser Sintering and Cold Isostatic Pressing to make complicated metal parts. In this paper, the specimens of stainless steel were made by the combined Selective Laser Sintering and Cold Isostatic Pressing forming route. And the simulation of Cold Isostatic Pressing was carried out by finite element method and Drucker-Prager-Cap constitutive model in ABAQUS/Explicit computer program. The property of metal powder was measured by experiments. The effects of bag on Cold Isostatic Pressing have been discussed. It is different from the Cold Isostatic Pressing of metal powder that the bag has little influence on both shape and size of the specimen. The results of simulation show a good agreement between the experimental results and the calculated results. The simulation can give a useful direction to dimension and shape designs of the combined forming of Selective Laser Sintering and Cold Isostatic Pressing.
David L Dl Bourell - One of the best experts on this subject based on the ideXlab platform.
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Effect of Phase Transformation on Densification During Hot Isostatic Pressing
Materials and Manufacturing Processes, 2007Co-Authors: Manoj Kumar Agarwala, David L Dl BourellAbstract:Abstract Densification of mixed phases which undergo phase transformation at elevated temperatures during hot Isostatic Pressing is described. The effect of the phase transformation on the densification process is shown relative to the densification characteristics of the major phase component of the mixed system. The densification of a mixed phase system undergoing phase transformation is compared using the mechanism maps for hot Isostatic Pressing of the single phase material. Densification of mixed phase systems undergoing phase transformation, such as homogenization with Kirkendall Effect, is considerably slower than its constituent single phase material. The tendency to generate Kirkendall pores due to homogenization of chemically different materials opposes the normal densification process, thus slowing down the densification process.
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Producing metal parts with selective laser sintering/hot Isostatic Pressing
JOM, 1999Co-Authors: Suman Das, Martin Wohlert, Joseph Jr Beaman, David L Dl BourellAbstract:Selective laser sintering/hot Isostatic Pressing is a hybrid direct laser fabrication method that combines the strengths of both processes. Selective laser sintering can produce complexly shaped metal components with an integral, gas-impermeable skin. These components can then be directly post-processed to full density by containerless hot Isostatic Pressing. The use of the hybrid fabrication method, envisioned as a rapid, low-cost replacement for conventional metal-can hot Isostatic Pressing, is currently being studied for alloy 625 and Ti-6Al-4V alloys. The microstructure and mechanical properties of selective-laser-sintering processed and hot Isostatically pressed post-processed material compare well with those of conventionally processed material.
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producing metal parts with selective laser sintering hot Isostatic Pressing
JOM, 1998Co-Authors: Martin Wohlert, David L Dl Bourell, Joseph Jr BeamanAbstract:Selective laser sintering/hot Isostatic Pressing is a hybrid direct laser fabrication method that combines the strengths of both processes. Selective laser sintering can produce complexly shaped metal components with an integral, gas-impermeable skin. These components can then be directly post-processed to full density by containerless hot Isostatic Pressing. The use of the hybrid fabrication method, envisioned as a rapid, low-cost replacement for conventional metal-can hot Isostatic Pressing, is currently being studied for alloy 625 and Ti-6Al-4V alloys. The micro-structure and mechanical properties of selective-laser-sintering processed and hot Isostatically pressed post-processed material compare well with those of conventionally processed material.
Freddy Yin Chiang Boey - One of the best experts on this subject based on the ideXlab platform.
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cold hot Isostatic Pressing of mar m200 superalloy powders
Journal of Materials Processing Technology, 1997Co-Authors: L S Ng, Freddy Yin Chiang BoeyAbstract:Abstract Powder metallurgy based on cold Isostatic Pressing, vacuum sintering and hot Isostatic Pressing (HIP) reveals the possibilities of mass producing critical parts in near net shape. The multi-stage process consists of: (i) cold Isostatic compaction to a green perform; (ii) supersolidus vacuum sintering of compact to more than 90% density; and (iii) final consolidation via hot Isostatic Pressing to densify the preform. Three-point flexural tests were carried out on the sintered and HIPped specimens. Microstructure and porosity evaluations were conducted using scanning electron microscopy and image analysis.
P A Carvalho - One of the best experts on this subject based on the ideXlab platform.
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consolidation of w ta composites hot Isostatic Pressing and spark and pulse plasma sintering
Fusion Engineering and Design, 2015Co-Authors: M. Dias, F Guerreiro, J B Correia, Andrei Galatanu, Marcin Rosinski, E Alves, Marco Antonio Sotelo Monge, A. Munoz, P A CarvalhoAbstract:Abstract Composites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot Isostatic Pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot Isostatic Pressing and pulse plasma sintering presented a continuous layer of Ta2O5 phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta2O5 eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot Isostatic Pressing and pulse plasma sintering.
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Consolidation of W–Ta composites: Hot Isostatic Pressing and spark and pulse plasma sintering
Fusion Engineering and Design, 2015Co-Authors: M. Dias, F Guerreiro, J B Correia, Andrei Galatanu, E Alves, M Rosin, Marco Antonio Sotelo Monge, A. Munoz, P A CarvalhoAbstract:Composites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot Isostatic Pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot Isostatic Pressing and pulse plasma sintering presented a continuous layer of Ta2O5 phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta2O5 eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot Isostatic Pressing and pulse plasma sintering
L S Ng - One of the best experts on this subject based on the ideXlab platform.
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cold hot Isostatic Pressing of mar m200 superalloy powders
Journal of Materials Processing Technology, 1997Co-Authors: L S Ng, Freddy Yin Chiang BoeyAbstract:Abstract Powder metallurgy based on cold Isostatic Pressing, vacuum sintering and hot Isostatic Pressing (HIP) reveals the possibilities of mass producing critical parts in near net shape. The multi-stage process consists of: (i) cold Isostatic compaction to a green perform; (ii) supersolidus vacuum sintering of compact to more than 90% density; and (iii) final consolidation via hot Isostatic Pressing to densify the preform. Three-point flexural tests were carried out on the sintered and HIPped specimens. Microstructure and porosity evaluations were conducted using scanning electron microscopy and image analysis.