The Experts below are selected from a list of 2460 Experts worldwide ranked by ideXlab platform
Hiroaki Takadama - One of the best experts on this subject based on the ideXlab platform.
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fabrication of dense α alumina layer on ti 6al 4v alloy hybrid for bearing surfaces of Artificial Hip Joint
Materials Science and Engineering: C, 2016Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:Recent advances in Hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationsHips in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of Artificial Hip Joint.
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novel Artificial Hip Joint a layer of alumina on ti 6al 4v alloy formed by micro arc oxidation
Materials Science and Engineering: C, 2015Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Yuuji Nomura, Norihiro Nose, Yoshiyuki Oomori, Takuya Yoshida, Koichi Wakita, Hiroaki TakadamaAbstract:In many Hip replacement surgeries, monolithic alumina is used as a femoral head due to its high wear resistance. However, it is liable to fracture under load bearing operations in Artificial Joints. We propose a promising way to overcome this limitation by forming a dense alumina layer onto a relatively tough substrate such as Ti-6Al-4V alloy to obtain high wear resistance on a material that can sustain relatively high toughness. For this purpose, Al metal powders were deposited onto Ti-6Al-4V alloy by cold spraying in N2 atmosphere. Interfacial adhesion between Al and the Ti alloy was improved by the formation of a reaction layer of Al3Ti between them by heating at 640 °C for 1h in air. Subsequently, micro-arc oxidation treatment was performed to oxidize Al. The oxidized layer was composed of an outer porous layer of γ-alumina and inner-most dense layer of α-alumina. The α-alumina layer was almost fully densified and exhibited high Vickers hardness almost equal to that of alumina ceramics used as the femoral head. Thus, the newly developed dense alumina/Ti alloy can be potentially used to produce the reliable bearing surfaces of Artificial Hip Joint.
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formation of alumina layer on ti alloy for Artificial Hip Joint
Key Engineering Materials, 2014Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:The purpose of this research is to form a layer of alumina on Ti-6Al-4V alloy for Hip Joint by deposition of Al layer on the Ti alloy and its subsequent oxidation. In this work, a thick layer of Al was deposited onto the Ti alloy by cold spraying. The reaction layer of Al3Ti was formed by heat treatment of cold sprayed Al at 640°C in air/Ar atmosphere to ensure a good adhesion between cold sprayed Al layer and the Ti alloy. A thick Al3Ti layer formed by heat treatment of Al layer at 640°C for 12 h in air, was subjected to heat treatment at 850°C for 96 h in air to form a-alumina and Al2Ti. Thus, alumina scales can be formed on the top surface of the Ti alloy and can be densified by increasing the time duration of heat treatment.
Rohit Khanna - One of the best experts on this subject based on the ideXlab platform.
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fabrication of dense α alumina layer on ti 6al 4v alloy hybrid for bearing surfaces of Artificial Hip Joint
Materials Science and Engineering: C, 2016Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:Recent advances in Hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationsHips in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of Artificial Hip Joint.
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novel Artificial Hip Joint a layer of alumina on ti 6al 4v alloy formed by micro arc oxidation
Materials Science and Engineering: C, 2015Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Yuuji Nomura, Norihiro Nose, Yoshiyuki Oomori, Takuya Yoshida, Koichi Wakita, Hiroaki TakadamaAbstract:In many Hip replacement surgeries, monolithic alumina is used as a femoral head due to its high wear resistance. However, it is liable to fracture under load bearing operations in Artificial Joints. We propose a promising way to overcome this limitation by forming a dense alumina layer onto a relatively tough substrate such as Ti-6Al-4V alloy to obtain high wear resistance on a material that can sustain relatively high toughness. For this purpose, Al metal powders were deposited onto Ti-6Al-4V alloy by cold spraying in N2 atmosphere. Interfacial adhesion between Al and the Ti alloy was improved by the formation of a reaction layer of Al3Ti between them by heating at 640 °C for 1h in air. Subsequently, micro-arc oxidation treatment was performed to oxidize Al. The oxidized layer was composed of an outer porous layer of γ-alumina and inner-most dense layer of α-alumina. The α-alumina layer was almost fully densified and exhibited high Vickers hardness almost equal to that of alumina ceramics used as the femoral head. Thus, the newly developed dense alumina/Ti alloy can be potentially used to produce the reliable bearing surfaces of Artificial Hip Joint.
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formation of alumina layer on ti alloy for Artificial Hip Joint
Key Engineering Materials, 2014Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:The purpose of this research is to form a layer of alumina on Ti-6Al-4V alloy for Hip Joint by deposition of Al layer on the Ti alloy and its subsequent oxidation. In this work, a thick layer of Al was deposited onto the Ti alloy by cold spraying. The reaction layer of Al3Ti was formed by heat treatment of cold sprayed Al at 640°C in air/Ar atmosphere to ensure a good adhesion between cold sprayed Al layer and the Ti alloy. A thick Al3Ti layer formed by heat treatment of Al layer at 640°C for 12 h in air, was subjected to heat treatment at 850°C for 96 h in air to form a-alumina and Al2Ti. Thus, alumina scales can be formed on the top surface of the Ti alloy and can be densified by increasing the time duration of heat treatment.
Ge Shirong - One of the best experts on this subject based on the ideXlab platform.
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research on the torsional fretting behavior of the head neck interface of Artificial Hip Joint
Materials & Design, 2014Co-Authors: Chen Kai, Zhang Dekun, Zhang Gaofeng, Hao Tianqing, Ge ShirongAbstract:Abstract The torsional fretting behavior of the head–neck interface of Artificial Hip Joint composed of Ti6Al4V and CoCrMo was investigated. The torsional fretting mechanisms were evaluated by experiments at various angular displacement amplitudes. The friction coefficient for the head–neck interface was calculated using contact mechanics. The head–neck interface model was established in accordance with the Artificial Hip Joint head–neck size. The conical angle and diameter of the Artificial Hip Joint head were optimized using data derived from the finite element method (FEM). The results indicate that torsional fretting changes from partial slip regime to slip regime with increasing angular displacement amplitude. Friction torque, friction dissipated energy, and the friction coefficient increase with increasing angular displacement amplitude and wear intensifies. Finite element simulation results demonstrate that self-locking occurs in the head–neck interface of Artificial Hip Joint more readily at small conical angles. The head–neck interface is least susceptible to fretting when the conical angle is 5°42′30″. Relative displacement and contact stress can be reduced by appropriately increasing the conical angle within a small angle range and increasing the Artificial Hip Joint head diameter, which can decrease fretting wear.
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Research on the torsional fretting behavior of the head–neck interface of Artificial Hip Joint
Materials & Design (1980-2015), 2014Co-Authors: Chen Kai, Zhang Dekun, Zhang Gaofeng, Hao Tianqing, Ge ShirongAbstract:Abstract The torsional fretting behavior of the head–neck interface of Artificial Hip Joint composed of Ti6Al4V and CoCrMo was investigated. The torsional fretting mechanisms were evaluated by experiments at various angular displacement amplitudes. The friction coefficient for the head–neck interface was calculated using contact mechanics. The head–neck interface model was established in accordance with the Artificial Hip Joint head–neck size. The conical angle and diameter of the Artificial Hip Joint head were optimized using data derived from the finite element method (FEM). The results indicate that torsional fretting changes from partial slip regime to slip regime with increasing angular displacement amplitude. Friction torque, friction dissipated energy, and the friction coefficient increase with increasing angular displacement amplitude and wear intensifies. Finite element simulation results demonstrate that self-locking occurs in the head–neck interface of Artificial Hip Joint more readily at small conical angles. The head–neck interface is least susceptible to fretting when the conical angle is 5°42′30″. Relative displacement and contact stress can be reduced by appropriately increasing the conical angle within a small angle range and increasing the Artificial Hip Joint head diameter, which can decrease fretting wear.
Tadashi Kokubo - One of the best experts on this subject based on the ideXlab platform.
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fabrication of dense α alumina layer on ti 6al 4v alloy hybrid for bearing surfaces of Artificial Hip Joint
Materials Science and Engineering: C, 2016Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:Recent advances in Hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationsHips in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of Artificial Hip Joint.
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novel Artificial Hip Joint a layer of alumina on ti 6al 4v alloy formed by micro arc oxidation
Materials Science and Engineering: C, 2015Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Yuuji Nomura, Norihiro Nose, Yoshiyuki Oomori, Takuya Yoshida, Koichi Wakita, Hiroaki TakadamaAbstract:In many Hip replacement surgeries, monolithic alumina is used as a femoral head due to its high wear resistance. However, it is liable to fracture under load bearing operations in Artificial Joints. We propose a promising way to overcome this limitation by forming a dense alumina layer onto a relatively tough substrate such as Ti-6Al-4V alloy to obtain high wear resistance on a material that can sustain relatively high toughness. For this purpose, Al metal powders were deposited onto Ti-6Al-4V alloy by cold spraying in N2 atmosphere. Interfacial adhesion between Al and the Ti alloy was improved by the formation of a reaction layer of Al3Ti between them by heating at 640 °C for 1h in air. Subsequently, micro-arc oxidation treatment was performed to oxidize Al. The oxidized layer was composed of an outer porous layer of γ-alumina and inner-most dense layer of α-alumina. The α-alumina layer was almost fully densified and exhibited high Vickers hardness almost equal to that of alumina ceramics used as the femoral head. Thus, the newly developed dense alumina/Ti alloy can be potentially used to produce the reliable bearing surfaces of Artificial Hip Joint.
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formation of alumina layer on ti alloy for Artificial Hip Joint
Key Engineering Materials, 2014Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:The purpose of this research is to form a layer of alumina on Ti-6Al-4V alloy for Hip Joint by deposition of Al layer on the Ti alloy and its subsequent oxidation. In this work, a thick layer of Al was deposited onto the Ti alloy by cold spraying. The reaction layer of Al3Ti was formed by heat treatment of cold sprayed Al at 640°C in air/Ar atmosphere to ensure a good adhesion between cold sprayed Al layer and the Ti alloy. A thick Al3Ti layer formed by heat treatment of Al layer at 640°C for 12 h in air, was subjected to heat treatment at 850°C for 96 h in air to form a-alumina and Al2Ti. Thus, alumina scales can be formed on the top surface of the Ti alloy and can be densified by increasing the time duration of heat treatment.
Tomiharu Matsushita - One of the best experts on this subject based on the ideXlab platform.
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fabrication of dense α alumina layer on ti 6al 4v alloy hybrid for bearing surfaces of Artificial Hip Joint
Materials Science and Engineering: C, 2016Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:Recent advances in Hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationsHips in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of Artificial Hip Joint.
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novel Artificial Hip Joint a layer of alumina on ti 6al 4v alloy formed by micro arc oxidation
Materials Science and Engineering: C, 2015Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Yuuji Nomura, Norihiro Nose, Yoshiyuki Oomori, Takuya Yoshida, Koichi Wakita, Hiroaki TakadamaAbstract:In many Hip replacement surgeries, monolithic alumina is used as a femoral head due to its high wear resistance. However, it is liable to fracture under load bearing operations in Artificial Joints. We propose a promising way to overcome this limitation by forming a dense alumina layer onto a relatively tough substrate such as Ti-6Al-4V alloy to obtain high wear resistance on a material that can sustain relatively high toughness. For this purpose, Al metal powders were deposited onto Ti-6Al-4V alloy by cold spraying in N2 atmosphere. Interfacial adhesion between Al and the Ti alloy was improved by the formation of a reaction layer of Al3Ti between them by heating at 640 °C for 1h in air. Subsequently, micro-arc oxidation treatment was performed to oxidize Al. The oxidized layer was composed of an outer porous layer of γ-alumina and inner-most dense layer of α-alumina. The α-alumina layer was almost fully densified and exhibited high Vickers hardness almost equal to that of alumina ceramics used as the femoral head. Thus, the newly developed dense alumina/Ti alloy can be potentially used to produce the reliable bearing surfaces of Artificial Hip Joint.
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formation of alumina layer on ti alloy for Artificial Hip Joint
Key Engineering Materials, 2014Co-Authors: Rohit Khanna, Tadashi Kokubo, Tomiharu Matsushita, Hiroaki TakadamaAbstract:The purpose of this research is to form a layer of alumina on Ti-6Al-4V alloy for Hip Joint by deposition of Al layer on the Ti alloy and its subsequent oxidation. In this work, a thick layer of Al was deposited onto the Ti alloy by cold spraying. The reaction layer of Al3Ti was formed by heat treatment of cold sprayed Al at 640°C in air/Ar atmosphere to ensure a good adhesion between cold sprayed Al layer and the Ti alloy. A thick Al3Ti layer formed by heat treatment of Al layer at 640°C for 12 h in air, was subjected to heat treatment at 850°C for 96 h in air to form a-alumina and Al2Ti. Thus, alumina scales can be formed on the top surface of the Ti alloy and can be densified by increasing the time duration of heat treatment.
