1998 Fiscal Year Annual Research Report

Ti-Ni系形状記憶合金単結晶におけるマルテンサイト変態と物性

Research Project

Project/Area Number	09044130
Research Institution	University of Tsukuba
Principal Investigator	大塚和弘筑波大学, 物質工学系, 教授 (50029881)
Co-Investigator(Kenkyū-buntansha)	KIREEVA I.V. シベリア物理工学研究所, 研究員 CHUMLYAKOV Y シベリア物理工学研究所, 教授任暁兵筑波大学, 物質工学系, 助手 (50292529) 大庭卓也帝京大学, 理工学部, 助教授 (00211110) 大嶋建一筑波大学, 物理工学系, 教授 (70109271)
Keywords	マルテンサイト変態 / 単結晶 / Ti-Ni単結晶 / 変態前駆現象 / R相変態 / Ti-Ni / Ti-Ni-Cu / Ti-Ni-Fe
Research Abstract	本年度はロシアで育成したTi-Ni系合金単結晶を用いて、それらの弾性定数を直方体共振方を用いて温度の関数をして系統的に測定し、弾性定数の温度依存性とマルテンサイト変態の間に極めて興味深い関係のあることを明らかにした。具体的には、Ti_<50-x>Ni_<50-x>、Ti_<50>Ni_<30>CU_<20>、Ti_<50>Ni_<40>CU_<10>合金単結晶の弾性定数を測定したが、これらのいずれにおいても、弾性定数c′、c_<44>共温度の低下に伴って軟化することが明らかになった。一方弾性異方性A-c_<44>/c′は斜方晶構造をとるTi-Ni系焼入れ材では温度の低下と共にAは減少するのに単斜晶構造をとるcu入りの後二者においてはAの増加することが明らかになった。しかもこの原因は以下のように考えるとよく説明できることを明らかにした。即ち、Ti-Ni2元系においては、変態点に近づくにしたがってAは上昇するので、{110}〈11^^-0〉shear-のみがdominantになり、斜方晶となる。これに反しCu入り系では、変態点に向かってAは1に近づいていき、{110}〈11^^-0〉shear-と{001}〈11^^-0〉shcarが同時に軟化するため単斜晶になる訳である。本研究は、マルテンサイト変態においてc_<44>が重要なことを初めて明らかにした研究と言うことができる。斜方晶構造を取るTi_<50>Ni_<30>Cu_<20>合金に対しフォノン分散関係を測定し、この合金に対しブリュワン・ゾーン境界でのフォノンのソフト化を初めて見出した。しがし〈11^^-0〉の1βの位置でのソフト化も観察しており、その解釈については今後研究を進めていく必要がある。 Ti-Ni-Fe合金におけるR相変態についても高エネルギー物理学研究所の放射光を用いて実験を行ったが、単結晶の結晶性が悪くハッキリした結論を得るには至らなかった。これについては更に研究を進めていく予定である。

Research Products

(17 results)

All Other

All Publications (17 results)

[Publications] X.Ren et al: "The Role of Softening in Elastic Constant c_<44> in Martensitic Transformation" Scripta Materialia. 38,11. 1169-1675 (1998)
[Publications] T.Tamiya et al.: "In-situ Observations of R-Phase Transformation in a Ti_<50>Ni_<48>Fe_2 Alloy by Electron Microscopy" Materials Trans.JIM. 39. 714-723 (1998)
[Publications] Y.Murakami et al.: "Electronic Structure Changes Associated with a Martensitic Transformation in Ti_<50>Ni_<48>Fe_2 Alloy Studied by Electron Energy-loss Spectroscopy" Journal of Electron Microscopy. 47(4). 301-309 (1998)
[Publications] X.Ren et al.: "Elastic Constants of Ti_<50>Ni_<30>Cu_<20> Alloy Prior to Martensitic Transformation" Philo.Mag.A. (in press).
[Publications] K.Otsuka et al.: "Martensitic Transformations in Nonferrous Shape Memory Alloys" Materials Sci.& Eng.(in press).
[Publications] K.Otsuka et al.: "Recent Developments in the Research of Shape Memory Alloys" Intermetallics. (in press).
[Publications] W.Cai et al.: "Study of R-phase Transformation in a Ti-50.7at%Ni Alloy by in situ TEM Observation" Materials Sci.& Eng.(in press).
[Publications] X.Ren et al.: "Understanding the Martensitic Transformations in TiNi-Based Alloys by Elastic Constant Measurement" Materials Sci.& Eng.(in press).
[Publications] Ken Gall et al.: "Tension-compression asymmetry of the stress-strain response in aged single crystal and polycrystaline Ni-Ti." Acta Materialia. (in press).
[Publications] Ken Gall et al.: "The influence of aging on critical transformation stress level and martensite start temperatures in Ni-Ti:part 1,Aged microstructure and micro-mechanical modeling" Journal of Engineering and Technology-Special Edition on Shape Memory Alloys. (in press).
[Publications] Ken Gall et al.: "The influence of aging on critical transformation stress level and martensite srart temperatures in Ni-Ti:part2,Dicussion of experimental results" Journal of Engineering and Technology-Special Edition on Shape Memory Alloys. (in press).
[Publications] Ken Gall et al.: "The role of coherent precipitates in martensitic transformations in single crystal and polycrystalline Ti-50.8 at % Ni" Scripta Materilia. (in press).
[Publications] Ken Gall et al.: "Pseudoelastic cyclic stress-strain response of over-aged single crystal Ti-50.8 at%Ni" Scripta Materilia. (in press).
[Publications] Yu I.Chumlyakov et al.: "The orientation dependences of shape memory effects and pseudoelasticity in single crystals Ti-30%Ni-20%Cu" Physics of Metals and Metallography. (in press).
[Publications] K.Otsuka et al.: "Shape Memory Materials" Cambridge University Press, 284 (1998)
[Publications] K.Inoue et al.: "Displacive Phase Transformations and Their Applications in Materials Engineering" Publication of TMS, 460 (1998)
[Publications] Youyi Chu et al.: "Proc.China-Japan Bilateral Symposium on Shape Memory Alloys" International Academic Publishers, 318 (1998)

1998 Fiscal Year Annual Research Report

Ti-Ni系形状記憶合金単結晶におけるマルテンサイト変態と物性

Principal Investigator

大塚 和弘 筑波大学, 物質工学系, 教授 (50029881)

Research Products

[Publications] X.Ren et al: "The Role of Softening in Elastic Constant c_<44> in Martensitic Transformation" Scripta Materialia. 38,11. 1169-1675 (1998)

[Publications] T.Tamiya et al.: "In-situ Observations of R-Phase Transformation in a Ti_<50>Ni_<48>Fe_2 Alloy by Electron Microscopy" Materials Trans.JIM. 39. 714-723 (1998)

[Publications] Y.Murakami et al.: "Electronic Structure Changes Associated with a Martensitic Transformation in Ti_<50>Ni_<48>Fe_2 Alloy Studied by Electron Energy-loss Spectroscopy" Journal of Electron Microscopy. 47(4). 301-309 (1998)

[Publications] X.Ren et al.: "Elastic Constants of Ti_<50>Ni_<30>Cu_<20> Alloy Prior to Martensitic Transformation" Philo.Mag.A. (in press).

[Publications] K.Otsuka et al.: "Martensitic Transformations in Nonferrous Shape Memory Alloys" Materials Sci.& Eng.(in press).

[Publications] K.Otsuka et al.: "Recent Developments in the Research of Shape Memory Alloys" Intermetallics. (in press).

[Publications] W.Cai et al.: "Study of R-phase Transformation in a Ti-50.7at%Ni Alloy by in situ TEM Observation" Materials Sci.& Eng.(in press).

[Publications] X.Ren et al.: "Understanding the Martensitic Transformations in TiNi-Based Alloys by Elastic Constant Measurement" Materials Sci.& Eng.(in press).

[Publications] Ken Gall et al.: "Tension-compression asymmetry of the stress-strain response in aged single crystal and polycrystaline Ni-Ti." Acta Materialia. (in press).

[Publications] Ken Gall et al.: "The influence of aging on critical transformation stress level and martensite start temperatures in Ni-Ti:part 1,Aged microstructure and micro-mechanical modeling" Journal of Engineering and Technology-Special Edition on Shape Memory Alloys. (in press).

[Publications] Ken Gall et al.: "The influence of aging on critical transformation stress level and martensite srart temperatures in Ni-Ti:part2,Dicussion of experimental results" Journal of Engineering and Technology-Special Edition on Shape Memory Alloys. (in press).

[Publications] Ken Gall et al.: "The role of coherent precipitates in martensitic transformations in single crystal and polycrystalline Ti-50.8 at % Ni" Scripta Materilia. (in press).

[Publications] Ken Gall et al.: "Pseudoelastic cyclic stress-strain response of over-aged single crystal Ti-50.8 at%Ni" Scripta Materilia. (in press).

[Publications] Yu I.Chumlyakov et al.: "The orientation dependences of shape memory effects and pseudoelasticity in single crystals Ti-30%Ni-20%Cu" Physics of Metals and Metallography. (in press).

[Publications] K.Otsuka et al.: "Shape Memory Materials" Cambridge University Press, 284 (1998)

[Publications] K.Inoue et al.: "Displacive Phase Transformations and Their Applications in Materials Engineering" Publication of TMS, 460 (1998)

[Publications] Youyi Chu et al.: "Proc.China-Japan Bilateral Symposium on Shape Memory Alloys" International Academic Publishers, 318 (1998)

大塚和弘筑波大学, 物質工学系, 教授 (50029881)