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Masuo Okada - One of the best experts on this subject based on the ideXlab platform.
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Isotope Effects on Protium.and Deuterium Absorption Properties in Ti-56 at%Cr-20 at%V Alloy
MATERIALS TRANSACTIONS, 2004Co-Authors: Takuya Tamura, Atsunori Kamegawa, Yoshiharu Katano, Hitoshi Takamura, Masuo OkadaAbstract:Ti-Cr-V alloys are known to absorb Protium.(hydrogen atom) up to H/M = 2. However, the Cr-rich alloys, e.g. Ti-Cr-20 at% V alloys containing more than 56 at%Cr, absorb up to H/M = 1 because of the formation of the mono-protides (mono-hydrides). The appearance region of the mono-dueteride was found to be more Cr-rich compositions than that of the mono-protides. For example, Ti-Cr-20 at% V alloys containing more than 60 at%Cr absorb deuterium up to D/M = 1. Therefore, Ti-56 at%Cr-20 at%V alloy absorbs Protium.up to H/M = I, but deuterium up to D/M = 2. As higher Protium.desorption capacity is achieved by increasing the Cr content in the region of the di-protide, there is some possibility of increasing the Protium.desorption capacity in Ti-Cr-V alloys using the isotope effects on absorption-desorption properties of the Ti-56 at%Cr-20 at%V alloy. This paper aims to clarify the isotope effects on Protium.and deuterium absorption properties in the Ti-56 at%Cr-20 at% V alloy. It was found that the memory effect for the absorption plateau pressure appears only once when deuterium was absorbed after desorbing Protium. and the memory effect for the absorption capacity appears when Protium.was absorbed after desorbing deuterium. The Protium.desorption capacity after deuterium treatment, namely, after desorbing deuterium showed twice as high as that without deuterium treatment in the Ti-56 at%Cr-20 at%V alloy. Increasing Protium.desorption capacity for deuterium treatment was caused by increasing di-protide formation and decreasing mono-protide formation.
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Protium.absorption properties and protide formations of Ti-Cr-V alloys
Journal of Alloys and Compounds, 2003Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Takashi Kazumi, Masuo OkadaAbstract:Abstract Ti–Cr–V alloys are known to absorb about 3.8 mass% (H/M=2) of Protium.(hydrogen atom), but to desorb about 2.4 mass%. This paper aims to clarify Protium.absorption properties and protide formations of Ti–Cr–V alloys. It was found that higher Protium.desorption capacity was achieved by increasing Cr content and controlling measurement temperature in order to control the desorption plateau pressure near atmospheric pressure for the alloys with less than 40 at% V content. However, Cr-rich alloys were found to absorb up to H/M=1 because of the formation of the mono-protides. The region with higher Protium.desorption capacity was obtained. The lattice parameters of the alloys and the enthalpy changes for di-protide formation were estimated from the compositions of the alloys. Moreover, estimated enthalpy changes for di-protide formation and the lattice parameters of the alloys were found to be generally constant on the limited line between appearance of regions of mono- and di-protides.
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Ti–Cr–X Protium.absorbing alloys with high Protium.content for fuel-cell
Journal of Alloys and Compounds, 2003Co-Authors: Masuo Okada, Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, T. Chou, A. Matsukawa, S. YamashitaAbstract:Abstract The effects of additional elements to the Ti–Cr alloys on their Protium.absorption–desorption properties were investigated. Although Ti–Cr alloys with a b.c.c. structure is expected to exhibit a high Protium.content, it is difficult to obtain single b.c.c. phase quenching from the high temperature. The effects of additional elements such as V, Mo, W, Nb, Ta, Ru, Rh, Re, Os, Ir etc. on stabilizing b.c.c. phase in the alloys were investigated. Then, it was found that the additions of V, Mo, W, Ru, Rh, Re, Os, Ir effectively stabilized b.c.c. phases. But the addition of Nb and Ta preferentially formed Laves phases. Specially, the addition of Mo and Ru is effective to stabilize the b.c.c. phases with high Protium.content. The Ti–Cr–(1∼2.5%)Mo alloys show almost same capacity of Protium.as that reported in Ti–Cr–(5–7.5)V alloys. The addition of Ru to Ti–Cr alloys also shows the capacity of 3.0 mass% Protium. These V-free Ti–Cr alloys will be also suitable for the future applications.
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Protium.absorption and desorption properties of bcc Ti-Fe solid solution alloys stabilized by Mo addition
MATERIALS TRANSACTIONS, 2003Co-Authors: Atsunori Kamegawa, Hitoshi Takamura, Hidehiro Kudo, Masuo OkadaAbstract:The present study investigates the effect of Mo addition to the TiFe alloys on a stabilization of bcc phase and their Protium.absorption and desorption properties. Ti 0.5 Fe 0.5 alloys with more than 10mol% Mo had CsCl phase and bcc phase, which show single plateaus in the PCT curves and were easily hydrogenated without homogenization. The bcc phase has larger lattice parameter than that of the CsCl phase. TiFe-10mol% Mo annealed alloys with the Ti/Fe ratio of more than 2 had a bcc phase as a main phase and CsCl as a minor one. The alloys had 3 mass% of the maximum Protium.capacity and desorbed Protium.only 1 mass%. The phases of the hydrogenated alloy were fcc and orthorhombic structure, which may be caused by di-hydrides of bcc solid solution and mono-hydrides of CsCl phase, respectively. It is found that the Mo addition to TiFe alloys could stabilize bcc phase and enhances the hydrogenation reaction of the disordered bcc Ti-Fe-Mo phase similar to Ti-Cr-X bcc alloys.
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Protium.absorption properties of Ti-Cr-V-Mn alloys in low pressure regions : Special issue on hydrogen absorbing materials
Materials Transactions Jim, 2002Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Masatoshi Hatakeyama, Toshiki Ebinuma, Masuo OkadaAbstract:The present study aims to investigate the effects of addition of Mn to Ti-Cr-V alloys on their Protium.absorption properties and to find the design criteria for increasing effective Protium.capacity. The effects of V and Mn content of the alloys on the Protium.absorption properties of heat-treated Ti-Cr-V-Mn alloys in low pressure regions were studied at various temperatures, and it was found that increasing Mn content and decreasing V content unstabilize protoride in low pressure region. The ACT curves from low pressure plateau region (10 -1 -10 5 Pa) to high pressure plateau region (10 5 -10 7 Pa) shifted to the side of low Protium.concentration. It was found that the addition of Mn or decreasing V content in the alloys is effective for increasing effective Protium.capacity.
Atsunori Kamegawa - One of the best experts on this subject based on the ideXlab platform.
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Isotope Effects on Protium.and Deuterium Absorption Properties in Ti-56 at%Cr-20 at%V Alloy
MATERIALS TRANSACTIONS, 2004Co-Authors: Takuya Tamura, Atsunori Kamegawa, Yoshiharu Katano, Hitoshi Takamura, Masuo OkadaAbstract:Ti-Cr-V alloys are known to absorb Protium.(hydrogen atom) up to H/M = 2. However, the Cr-rich alloys, e.g. Ti-Cr-20 at% V alloys containing more than 56 at%Cr, absorb up to H/M = 1 because of the formation of the mono-protides (mono-hydrides). The appearance region of the mono-dueteride was found to be more Cr-rich compositions than that of the mono-protides. For example, Ti-Cr-20 at% V alloys containing more than 60 at%Cr absorb deuterium up to D/M = 1. Therefore, Ti-56 at%Cr-20 at%V alloy absorbs Protium.up to H/M = I, but deuterium up to D/M = 2. As higher Protium.desorption capacity is achieved by increasing the Cr content in the region of the di-protide, there is some possibility of increasing the Protium.desorption capacity in Ti-Cr-V alloys using the isotope effects on absorption-desorption properties of the Ti-56 at%Cr-20 at%V alloy. This paper aims to clarify the isotope effects on Protium.and deuterium absorption properties in the Ti-56 at%Cr-20 at% V alloy. It was found that the memory effect for the absorption plateau pressure appears only once when deuterium was absorbed after desorbing Protium. and the memory effect for the absorption capacity appears when Protium.was absorbed after desorbing deuterium. The Protium.desorption capacity after deuterium treatment, namely, after desorbing deuterium showed twice as high as that without deuterium treatment in the Ti-56 at%Cr-20 at%V alloy. Increasing Protium.desorption capacity for deuterium treatment was caused by increasing di-protide formation and decreasing mono-protide formation.
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Ti–Cr–X Protium.absorbing alloys with high Protium.content for fuel-cell
Journal of Alloys and Compounds, 2003Co-Authors: Masuo Okada, Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, T. Chou, A. Matsukawa, S. YamashitaAbstract:Abstract The effects of additional elements to the Ti–Cr alloys on their Protium.absorption–desorption properties were investigated. Although Ti–Cr alloys with a b.c.c. structure is expected to exhibit a high Protium.content, it is difficult to obtain single b.c.c. phase quenching from the high temperature. The effects of additional elements such as V, Mo, W, Nb, Ta, Ru, Rh, Re, Os, Ir etc. on stabilizing b.c.c. phase in the alloys were investigated. Then, it was found that the additions of V, Mo, W, Ru, Rh, Re, Os, Ir effectively stabilized b.c.c. phases. But the addition of Nb and Ta preferentially formed Laves phases. Specially, the addition of Mo and Ru is effective to stabilize the b.c.c. phases with high Protium.content. The Ti–Cr–(1∼2.5%)Mo alloys show almost same capacity of Protium.as that reported in Ti–Cr–(5–7.5)V alloys. The addition of Ru to Ti–Cr alloys also shows the capacity of 3.0 mass% Protium. These V-free Ti–Cr alloys will be also suitable for the future applications.
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Protium.absorption properties and protide formations of Ti-Cr-V alloys
Journal of Alloys and Compounds, 2003Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Takashi Kazumi, Masuo OkadaAbstract:Abstract Ti–Cr–V alloys are known to absorb about 3.8 mass% (H/M=2) of Protium.(hydrogen atom), but to desorb about 2.4 mass%. This paper aims to clarify Protium.absorption properties and protide formations of Ti–Cr–V alloys. It was found that higher Protium.desorption capacity was achieved by increasing Cr content and controlling measurement temperature in order to control the desorption plateau pressure near atmospheric pressure for the alloys with less than 40 at% V content. However, Cr-rich alloys were found to absorb up to H/M=1 because of the formation of the mono-protides. The region with higher Protium.desorption capacity was obtained. The lattice parameters of the alloys and the enthalpy changes for di-protide formation were estimated from the compositions of the alloys. Moreover, estimated enthalpy changes for di-protide formation and the lattice parameters of the alloys were found to be generally constant on the limited line between appearance of regions of mono- and di-protides.
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Protium.absorption and desorption properties of bcc Ti-Fe solid solution alloys stabilized by Mo addition
MATERIALS TRANSACTIONS, 2003Co-Authors: Atsunori Kamegawa, Hitoshi Takamura, Hidehiro Kudo, Masuo OkadaAbstract:The present study investigates the effect of Mo addition to the TiFe alloys on a stabilization of bcc phase and their Protium.absorption and desorption properties. Ti 0.5 Fe 0.5 alloys with more than 10mol% Mo had CsCl phase and bcc phase, which show single plateaus in the PCT curves and were easily hydrogenated without homogenization. The bcc phase has larger lattice parameter than that of the CsCl phase. TiFe-10mol% Mo annealed alloys with the Ti/Fe ratio of more than 2 had a bcc phase as a main phase and CsCl as a minor one. The alloys had 3 mass% of the maximum Protium.capacity and desorbed Protium.only 1 mass%. The phases of the hydrogenated alloy were fcc and orthorhombic structure, which may be caused by di-hydrides of bcc solid solution and mono-hydrides of CsCl phase, respectively. It is found that the Mo addition to TiFe alloys could stabilize bcc phase and enhances the hydrogenation reaction of the disordered bcc Ti-Fe-Mo phase similar to Ti-Cr-X bcc alloys.
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Protium.absorption properties of Ti-Cr-V-Mn alloys in low pressure regions : Special issue on hydrogen absorbing materials
Materials Transactions Jim, 2002Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Masatoshi Hatakeyama, Toshiki Ebinuma, Masuo OkadaAbstract:The present study aims to investigate the effects of addition of Mn to Ti-Cr-V alloys on their Protium.absorption properties and to find the design criteria for increasing effective Protium.capacity. The effects of V and Mn content of the alloys on the Protium.absorption properties of heat-treated Ti-Cr-V-Mn alloys in low pressure regions were studied at various temperatures, and it was found that increasing Mn content and decreasing V content unstabilize protoride in low pressure region. The ACT curves from low pressure plateau region (10 -1 -10 5 Pa) to high pressure plateau region (10 5 -10 7 Pa) shifted to the side of low Protium.concentration. It was found that the addition of Mn or decreasing V content in the alloys is effective for increasing effective Protium.capacity.
Hitoshi Takamura - One of the best experts on this subject based on the ideXlab platform.
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Isotope Effects on Protium.and Deuterium Absorption Properties in Ti-56 at%Cr-20 at%V Alloy
MATERIALS TRANSACTIONS, 2004Co-Authors: Takuya Tamura, Atsunori Kamegawa, Yoshiharu Katano, Hitoshi Takamura, Masuo OkadaAbstract:Ti-Cr-V alloys are known to absorb Protium.(hydrogen atom) up to H/M = 2. However, the Cr-rich alloys, e.g. Ti-Cr-20 at% V alloys containing more than 56 at%Cr, absorb up to H/M = 1 because of the formation of the mono-protides (mono-hydrides). The appearance region of the mono-dueteride was found to be more Cr-rich compositions than that of the mono-protides. For example, Ti-Cr-20 at% V alloys containing more than 60 at%Cr absorb deuterium up to D/M = 1. Therefore, Ti-56 at%Cr-20 at%V alloy absorbs Protium.up to H/M = I, but deuterium up to D/M = 2. As higher Protium.desorption capacity is achieved by increasing the Cr content in the region of the di-protide, there is some possibility of increasing the Protium.desorption capacity in Ti-Cr-V alloys using the isotope effects on absorption-desorption properties of the Ti-56 at%Cr-20 at%V alloy. This paper aims to clarify the isotope effects on Protium.and deuterium absorption properties in the Ti-56 at%Cr-20 at% V alloy. It was found that the memory effect for the absorption plateau pressure appears only once when deuterium was absorbed after desorbing Protium. and the memory effect for the absorption capacity appears when Protium.was absorbed after desorbing deuterium. The Protium.desorption capacity after deuterium treatment, namely, after desorbing deuterium showed twice as high as that without deuterium treatment in the Ti-56 at%Cr-20 at%V alloy. Increasing Protium.desorption capacity for deuterium treatment was caused by increasing di-protide formation and decreasing mono-protide formation.
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Ti–Cr–X Protium.absorbing alloys with high Protium.content for fuel-cell
Journal of Alloys and Compounds, 2003Co-Authors: Masuo Okada, Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, T. Chou, A. Matsukawa, S. YamashitaAbstract:Abstract The effects of additional elements to the Ti–Cr alloys on their Protium.absorption–desorption properties were investigated. Although Ti–Cr alloys with a b.c.c. structure is expected to exhibit a high Protium.content, it is difficult to obtain single b.c.c. phase quenching from the high temperature. The effects of additional elements such as V, Mo, W, Nb, Ta, Ru, Rh, Re, Os, Ir etc. on stabilizing b.c.c. phase in the alloys were investigated. Then, it was found that the additions of V, Mo, W, Ru, Rh, Re, Os, Ir effectively stabilized b.c.c. phases. But the addition of Nb and Ta preferentially formed Laves phases. Specially, the addition of Mo and Ru is effective to stabilize the b.c.c. phases with high Protium.content. The Ti–Cr–(1∼2.5%)Mo alloys show almost same capacity of Protium.as that reported in Ti–Cr–(5–7.5)V alloys. The addition of Ru to Ti–Cr alloys also shows the capacity of 3.0 mass% Protium. These V-free Ti–Cr alloys will be also suitable for the future applications.
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Protium.absorption properties and protide formations of Ti-Cr-V alloys
Journal of Alloys and Compounds, 2003Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Takashi Kazumi, Masuo OkadaAbstract:Abstract Ti–Cr–V alloys are known to absorb about 3.8 mass% (H/M=2) of Protium.(hydrogen atom), but to desorb about 2.4 mass%. This paper aims to clarify Protium.absorption properties and protide formations of Ti–Cr–V alloys. It was found that higher Protium.desorption capacity was achieved by increasing Cr content and controlling measurement temperature in order to control the desorption plateau pressure near atmospheric pressure for the alloys with less than 40 at% V content. However, Cr-rich alloys were found to absorb up to H/M=1 because of the formation of the mono-protides. The region with higher Protium.desorption capacity was obtained. The lattice parameters of the alloys and the enthalpy changes for di-protide formation were estimated from the compositions of the alloys. Moreover, estimated enthalpy changes for di-protide formation and the lattice parameters of the alloys were found to be generally constant on the limited line between appearance of regions of mono- and di-protides.
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Protium.absorption and desorption properties of bcc Ti-Fe solid solution alloys stabilized by Mo addition
MATERIALS TRANSACTIONS, 2003Co-Authors: Atsunori Kamegawa, Hitoshi Takamura, Hidehiro Kudo, Masuo OkadaAbstract:The present study investigates the effect of Mo addition to the TiFe alloys on a stabilization of bcc phase and their Protium.absorption and desorption properties. Ti 0.5 Fe 0.5 alloys with more than 10mol% Mo had CsCl phase and bcc phase, which show single plateaus in the PCT curves and were easily hydrogenated without homogenization. The bcc phase has larger lattice parameter than that of the CsCl phase. TiFe-10mol% Mo annealed alloys with the Ti/Fe ratio of more than 2 had a bcc phase as a main phase and CsCl as a minor one. The alloys had 3 mass% of the maximum Protium.capacity and desorbed Protium.only 1 mass%. The phases of the hydrogenated alloy were fcc and orthorhombic structure, which may be caused by di-hydrides of bcc solid solution and mono-hydrides of CsCl phase, respectively. It is found that the Mo addition to TiFe alloys could stabilize bcc phase and enhances the hydrogenation reaction of the disordered bcc Ti-Fe-Mo phase similar to Ti-Cr-X bcc alloys.
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Protium.absorption properties of Ti-Cr-V-Mn alloys in low pressure regions : Special issue on hydrogen absorbing materials
Materials Transactions Jim, 2002Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Masatoshi Hatakeyama, Toshiki Ebinuma, Masuo OkadaAbstract:The present study aims to investigate the effects of addition of Mn to Ti-Cr-V alloys on their Protium.absorption properties and to find the design criteria for increasing effective Protium.capacity. The effects of V and Mn content of the alloys on the Protium.absorption properties of heat-treated Ti-Cr-V-Mn alloys in low pressure regions were studied at various temperatures, and it was found that increasing Mn content and decreasing V content unstabilize protoride in low pressure region. The ACT curves from low pressure plateau region (10 -1 -10 5 Pa) to high pressure plateau region (10 5 -10 7 Pa) shifted to the side of low Protium.concentration. It was found that the addition of Mn or decreasing V content in the alloys is effective for increasing effective Protium.capacity.
Takuya Tamura - One of the best experts on this subject based on the ideXlab platform.
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Isotope Effects on Protium.and Deuterium Absorption Properties in Ti-56 at%Cr-20 at%V Alloy
MATERIALS TRANSACTIONS, 2004Co-Authors: Takuya Tamura, Atsunori Kamegawa, Yoshiharu Katano, Hitoshi Takamura, Masuo OkadaAbstract:Ti-Cr-V alloys are known to absorb Protium.(hydrogen atom) up to H/M = 2. However, the Cr-rich alloys, e.g. Ti-Cr-20 at% V alloys containing more than 56 at%Cr, absorb up to H/M = 1 because of the formation of the mono-protides (mono-hydrides). The appearance region of the mono-dueteride was found to be more Cr-rich compositions than that of the mono-protides. For example, Ti-Cr-20 at% V alloys containing more than 60 at%Cr absorb deuterium up to D/M = 1. Therefore, Ti-56 at%Cr-20 at%V alloy absorbs Protium.up to H/M = I, but deuterium up to D/M = 2. As higher Protium.desorption capacity is achieved by increasing the Cr content in the region of the di-protide, there is some possibility of increasing the Protium.desorption capacity in Ti-Cr-V alloys using the isotope effects on absorption-desorption properties of the Ti-56 at%Cr-20 at%V alloy. This paper aims to clarify the isotope effects on Protium.and deuterium absorption properties in the Ti-56 at%Cr-20 at% V alloy. It was found that the memory effect for the absorption plateau pressure appears only once when deuterium was absorbed after desorbing Protium. and the memory effect for the absorption capacity appears when Protium.was absorbed after desorbing deuterium. The Protium.desorption capacity after deuterium treatment, namely, after desorbing deuterium showed twice as high as that without deuterium treatment in the Ti-56 at%Cr-20 at%V alloy. Increasing Protium.desorption capacity for deuterium treatment was caused by increasing di-protide formation and decreasing mono-protide formation.
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Ti–Cr–X Protium.absorbing alloys with high Protium.content for fuel-cell
Journal of Alloys and Compounds, 2003Co-Authors: Masuo Okada, Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, T. Chou, A. Matsukawa, S. YamashitaAbstract:Abstract The effects of additional elements to the Ti–Cr alloys on their Protium.absorption–desorption properties were investigated. Although Ti–Cr alloys with a b.c.c. structure is expected to exhibit a high Protium.content, it is difficult to obtain single b.c.c. phase quenching from the high temperature. The effects of additional elements such as V, Mo, W, Nb, Ta, Ru, Rh, Re, Os, Ir etc. on stabilizing b.c.c. phase in the alloys were investigated. Then, it was found that the additions of V, Mo, W, Ru, Rh, Re, Os, Ir effectively stabilized b.c.c. phases. But the addition of Nb and Ta preferentially formed Laves phases. Specially, the addition of Mo and Ru is effective to stabilize the b.c.c. phases with high Protium.content. The Ti–Cr–(1∼2.5%)Mo alloys show almost same capacity of Protium.as that reported in Ti–Cr–(5–7.5)V alloys. The addition of Ru to Ti–Cr alloys also shows the capacity of 3.0 mass% Protium. These V-free Ti–Cr alloys will be also suitable for the future applications.
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Protium.absorption properties and protide formations of Ti-Cr-V alloys
Journal of Alloys and Compounds, 2003Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Takashi Kazumi, Masuo OkadaAbstract:Abstract Ti–Cr–V alloys are known to absorb about 3.8 mass% (H/M=2) of Protium.(hydrogen atom), but to desorb about 2.4 mass%. This paper aims to clarify Protium.absorption properties and protide formations of Ti–Cr–V alloys. It was found that higher Protium.desorption capacity was achieved by increasing Cr content and controlling measurement temperature in order to control the desorption plateau pressure near atmospheric pressure for the alloys with less than 40 at% V content. However, Cr-rich alloys were found to absorb up to H/M=1 because of the formation of the mono-protides. The region with higher Protium.desorption capacity was obtained. The lattice parameters of the alloys and the enthalpy changes for di-protide formation were estimated from the compositions of the alloys. Moreover, estimated enthalpy changes for di-protide formation and the lattice parameters of the alloys were found to be generally constant on the limited line between appearance of regions of mono- and di-protides.
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Protium.absorption properties of Ti-Cr-V-Mn alloys in low pressure regions : Special issue on hydrogen absorbing materials
Materials Transactions Jim, 2002Co-Authors: Takuya Tamura, Atsunori Kamegawa, Hitoshi Takamura, Masatoshi Hatakeyama, Toshiki Ebinuma, Masuo OkadaAbstract:The present study aims to investigate the effects of addition of Mn to Ti-Cr-V alloys on their Protium.absorption properties and to find the design criteria for increasing effective Protium.capacity. The effects of V and Mn content of the alloys on the Protium.absorption properties of heat-treated Ti-Cr-V-Mn alloys in low pressure regions were studied at various temperatures, and it was found that increasing Mn content and decreasing V content unstabilize protoride in low pressure region. The ACT curves from low pressure plateau region (10 -1 -10 5 Pa) to high pressure plateau region (10 5 -10 7 Pa) shifted to the side of low Protium.concentration. It was found that the addition of Mn or decreasing V content in the alloys is effective for increasing effective Protium.capacity.
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Effects of Al addition on structures and Protium.absorption-desorption properties of Ti-Cr alloys
MATERIALS TRANSACTIONS, 2002Co-Authors: Koji Shirasaki, Takuya Tamura, Takahiro Kuriiwa, Atsunori Kamegawa, Hitoshi Takamura, Masuo OkadaAbstract:The effects of Al addition on structures and Protium.absorption-desorption properties of Ti–Cr alloys were investigated. It was foundthat 1at% Al addition is effective for improvement of Protium.storage capacity. The BCC phase increases with increasing Al content in Ti–Cr–Al alloys. It is generally well known that plateau pressure of the Protium.storage alloys, e.g. Ti–Cr-V and Ti–Fe–V alloys, increases withdecreasing lattice constants, however, the plateau pressure of the Ti–Cr–Al alloys increases with increasing lattice constants, namely increasin gAl content.(Received January 15, 2002; Accepted March 7, 2002)Keywords: Protium.storage alloy, body centered cubic phase, titanium–chromium–aluminum alloy
Jun Nakahigashi - One of the best experts on this subject based on the ideXlab platform.
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Superplasticity and its application of ultra-fine grained Ti-6Al-4V alloy obtained through Protium.treatment
MATERIALS TRANSACTIONS, 2002Co-Authors: Jun Nakahigashi, Hirofumi YoshimuraAbstract:Superplastic-tensile test and superplastic forming for the denture base (One of the dental parts) were carried out experimentally using an a + β two-phase type Ti-6Al-4V alloy with an ultra-fine grained structure (grain size: 0.3-0.5 μm) obtained through Protium.treatment. The ultra-fine grained material exhibited a significant superplastic elongation of over 9000% at 1123 K and a flow stress lower than that of coarse-grained material made from the same alloy without Protium.treatments. Superplastic forming was successfully used to fabricate a denture base without cracks on the surface. These materials may be applicable as biomaterials in medical industries.
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Ultra-fine grain refinement and tensile properties of titanium alloys obtained through Protium.treatment
Journal of Alloys and Compounds, 2001Co-Authors: Jun Nakahigashi, Hirofumi YoshimuraAbstract:Abstract One of the few methods available for creating fine grains of metallic materials is Protium.treatment, which has been demonstrated to readily produce a fine-grain size of 1–3 μm in α+β type Ti–6Al–4V alloys. However the minimum grain size obtainable by this treatment is not yet known. The purpose of the present investigation is to obtain submicron grain sizes or less through improvement of the Protium.treatment conditions by varying the Protium.absorption content and lowering the Protium.desorption temperature. Tensile tests at room temperature and superplasticity tensile tests at elevated temperature in vacuum were carried out to study the tensile properties of the materials obtained in this investigation. The experimental results are as follows. Ultra-fine grained titanium alloys (grain size 0.3–0.5 μm) are obtained through a process in which 0.5 mass% of Protium.is absorbed and the Protium.desorption temperature is lowered from 973 to 873 K. The β-phase percentage in the α-phase matrix tends to increase as a result of this treatment. The yield strength of the ultra-fine grained materials is improved in accordance with the Hall–Petch law. Such materials show high elongation for high strength. The ultra-fine grained material exhibits a superplastic elongation of over 6000% at a test temperature of 1073 K with a strain rate of 1×10 −3 s −1 .
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Ultra-fine-grain refinement and superplasticity of titanium alloys obtained through Protium.treatment
International Journal of Hydrogen Energy, 2001Co-Authors: Hirofumi Yoshimura, Jun NakahigashiAbstract:Abstract Titanium alloys absorb large amounts of hydrogen atoms (Protium. which are desorbed in vacuum at elevated temperatures. The treatment utilizing this phenomenon is called Protium.treatment. Our studies of this treatment are reviewed and recent experimental results are introduced. Protium.treatment consists of the following three processes for a+s type titanium alloys: (1) Protium.absorption, (2) martensitic transformation and hot working, and (3) final treatment for Protium.desorption and recrystallization. A combination of these processes results in the ultra-fine grains of 0.3– 0.5 μm in diameter with high angle boundaries. The fine-grained material shows improved 0.2% proof stress at room temperature and exhibits a superplastic elongation of over 9000%. This is considered to be due to the ultra-fine-grain refinement and the higher proportion of the s-phase in an a-phase matrix.
