The Experts below are selected from a list of 165 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 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.
Walter José Botta - One of the best experts on this subject based on the ideXlab platform.
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Processing of Al matrix composites reinforced with Al-Ni compounds and Al2O3 by reactive milling and reactive sintering
Journal of Alloys and Compounds, 2008Co-Authors: J.b. Fogagnolo, Eliria Maria De Jesus Agnolon Pallone, D.r. Martin, C.s. Kiminami, C. Bolfarini, Walter José BottaAbstract:Abstract Aluminum matrix composites reinforced with Al–Ni intermetallic compounds and Al 2 O 3 were obtained by hot Pressing of high-energy milled powders. Using the reaction between Al and NiO and aiming to preserve part of the Al content after completing the reaction by increasing the relative amount of Al, composites containing Al 2 O 3 and Al–Ni intermetallic compounds were produced. These composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Depending on the Al/NiO molar ratio, the reaction can be activated either during milling or during subsequent hot Pressing. Hence, two different processing routes can be used to produce such composites. Starting from powder mixtures with an Al/NiO molar ratio of 15/3, the reaction took place during milling, Forming Al 3 Ni and Al 3 Ni 2 plus Al 2 O 3 reinforced Al composite powder, which was consolidated by hot Pressing. An Al/NiO molar ratio of 20/3 prevented the reaction from occurring during milling, but enabled it to occur during subsequent hot Pressing, Forming the same reinforcement phases. The reactive-milled composite is harder and presents higher porosity than the reactive-sintered ones, after consolidation by hot Pressing under the same parameters. In the latter route, the longer the milling time prior to hot Pressing, the smaller the size of the reinforcement phases.
O. Gingu - One of the best experts on this subject based on the ideXlab platform.
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Studies concerning the optimization of ceramic magnets anisotrope Pressing
Journal of Materials Processing Technology, 1999Co-Authors: M. Mangra, M. Ivanescu, V. Stoian, O. GinguAbstract:Abstract This paper presents some research results concerning the optimization of the wet anisotrope Pressing of Ba and Sr ferrite powders. The increasing of the structural anisotropy degree – K – of the permanent ceramic magnets by the addition of some surfactants to the liquid of the Pressing slurries is the main purpose of this research. Also, there is an exploration of the optimization effects on the anisotrope Pressing Forming operation from the point of view of the relationship between the microstructural anisotropy degree – K – and the energy improvement – BHmax – of the manufactured magnets.
J.b. Fogagnolo - One of the best experts on this subject based on the ideXlab platform.
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Processing of Al matrix composites reinforced with Al-Ni compounds and Al2O3 by reactive milling and reactive sintering
Journal of Alloys and Compounds, 2008Co-Authors: J.b. Fogagnolo, Eliria Maria De Jesus Agnolon Pallone, D.r. Martin, C.s. Kiminami, C. Bolfarini, Walter José BottaAbstract:Abstract Aluminum matrix composites reinforced with Al–Ni intermetallic compounds and Al 2 O 3 were obtained by hot Pressing of high-energy milled powders. Using the reaction between Al and NiO and aiming to preserve part of the Al content after completing the reaction by increasing the relative amount of Al, composites containing Al 2 O 3 and Al–Ni intermetallic compounds were produced. These composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Depending on the Al/NiO molar ratio, the reaction can be activated either during milling or during subsequent hot Pressing. Hence, two different processing routes can be used to produce such composites. Starting from powder mixtures with an Al/NiO molar ratio of 15/3, the reaction took place during milling, Forming Al 3 Ni and Al 3 Ni 2 plus Al 2 O 3 reinforced Al composite powder, which was consolidated by hot Pressing. An Al/NiO molar ratio of 20/3 prevented the reaction from occurring during milling, but enabled it to occur during subsequent hot Pressing, Forming the same reinforcement phases. The reactive-milled composite is harder and presents higher porosity than the reactive-sintered ones, after consolidation by hot Pressing under the same parameters. In the latter route, the longer the milling time prior to hot Pressing, the smaller the size of the reinforcement phases.
M. Mangra - One of the best experts on this subject based on the ideXlab platform.
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Studies concerning the optimization of ceramic magnets anisotrope Pressing
Journal of Materials Processing Technology, 1999Co-Authors: M. Mangra, M. Ivanescu, V. Stoian, O. GinguAbstract:Abstract This paper presents some research results concerning the optimization of the wet anisotrope Pressing of Ba and Sr ferrite powders. The increasing of the structural anisotropy degree – K – of the permanent ceramic magnets by the addition of some surfactants to the liquid of the Pressing slurries is the main purpose of this research. Also, there is an exploration of the optimization effects on the anisotrope Pressing Forming operation from the point of view of the relationship between the microstructural anisotropy degree – K – and the energy improvement – BHmax – of the manufactured magnets.