New developments on displacive phase transformations

位移相变的新进展

• 批准号: 09242103
• 负责人: OTSUKA Kazuhiro
• 金额: $ 58.18万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-09242103/
• 关键词: displacive phase transformation; martensitic transformation; pretransformation phenomena; lattice defects; kinetics of transformation; shape-memory thin films; nano-particles; lattice softening; ゴム弾性的挙動; 形状記憶効果; Ti-Ni薄膜

For the five themes studied in this group, the abstracts of the results are described for each theme.(a) The mechanism of 1st order displacive transformations : The elastic constants of Ti-Ni alloy system (Ti-Ni, Ti-Ni-Cu, Ti-Ni-Fe) were measured systematically by utilizing "the parallelepiped resonance method" prior to the martensitic transformations. As a result, close relations were found to exist between the three kinds of martensitic transformations and the temperature dependence of elastic constants (c', c_<44>), and elastic anusotropy (A ≡ c_<44>/c').(b) The interaction of lattice defects with 1st order displacive transformation : The all aspects of the long-standing problem of "rubber-like behavior" was consistently explained by introducing "SC-SRO (Symmetry-Conforming Short Range Order) principle" (Nature, 1997) with respect to point defects upon displacive transformation. Furthermore, other new phenomena such as "microstructure memory" and "two-way shape memory" effects were … More found based on this principle (Phys.Rev.Lett., 2000).(c) New approach to thermodynamics of 1st order displacive transformations : For Kakeshita's theory, who treated athermal and isothermal martensitic transformations in a unified manner, systematic experiments were carried out. Thus the theory was justified by showing that an isothermal transformation will change into athermal one under magnetic field, and an athermal one into an isothermal one under hydrostatic pressure etc.(d) 1st order displacive transformations in thin films : The structures of Ti-Ni thin films produced by sputter-deposition technique were systematically studied by TEM.As a result, five precipitation states were found to exist as a function of composition and aging temperature.(e) 1st order displacive transformations in nanometer-sized alloy paricles : The martensitic transformations of nano-particles of Au-Cd and Fe-Ni alloys were observed in-situ by TEM, by using a newly developed apparatus directly connected TEM and vacuum evaporation chamber. As a result, the transformations temperatures of the alloys were found to decrease greatly, but the cause was found not to be explained by the previous theory. Less

对于本组研究的五个主题，对每个主题的结果进行了摘要描述。（a）一阶位移相变的机理：在马氏体相变之前，利用“平行六面体共振法”系统地测量了Ti-Ni合金系（Ti-Ni、Ti-Ni-Cu、Ti-Ni-Fe）的弹性常数。结果发现，三种马氏体转变与弹性常数（c'，c_<44>）和弹性各向异性（A ≡ c_<44>/c'）的温度依赖性之间存在密切关系。（b）晶格缺陷与一阶位移转变的相互作用：通过引入一致地解释了长期存在的“类橡胶行为”问题的各个方面 “SC-SRO（对称性短程有序）原理”（Nature，1997）关于位移变换时的点缺陷。此外，基于这一原理，还发现了“微观结构记忆”和“双向形状记忆”效应等新现象（Phys.Rev.Lett.，2000）。（c）一阶位移变换热力学的新方法：针对挂下统一处理无温和等温马氏体转变的理论，进行了系统的实验。因此，该理论通过证明等温转变将在磁场下转变为无热转变，以及在静水压力等情况下由无热转变为等温转变来证明。(d)薄膜中的一阶位移转变：通过TEM系统地研究了溅射沉积技术生产的Ti-Ni薄膜的结构。结果发现，存在五种析出状态，作为成分和老化温度的函数。(e) 纳米尺寸合金颗粒中的一阶位移转变：使用新开发的直接连接 TEM 和真空蒸发室的装置，通过 TEM 现场观察 Au-Cd 和 Fe-Ni 合金纳米颗粒的马氏体转变。结果发现合金的相变温度大大降低，但之前的理论无法解释其原因。较少的

项目成果

K.Otsuka, C.M.Wayman: "Shape Memory Materials"Cambridge University Press. 284 (1998)

K.Otsuka、C.M.Wayman：“形状记忆材料”剑桥大学出版社。

X.Ren: "Origin of rubber-like behavior in metal alloys"Nature. 389/6651. 579-582 (1997)

X.Ren：“金属合金中类橡胶行为的起源”自然。

X.Ren.et al.: "A Unified Model for Point-Defect Formation in B2 Intermetallic Compound's"Philo.Mag.A. (in press). (2000)

X.Ren.et al.：“B2 金属间化合物中点缺陷形成的统一模型”Philo.Mag.A.

M.Kozuma et al.: "Effect of Ageing the R-phase in Ti-Ni Based Alloys" Proc.of Displacive Phase Transformations and Their Applications in Materials Engineering. 233-238 (1998)

M.Kozuma 等人：“Ti-Ni 基合金中 R 相的时效效应”Proc.of Displacive Phase Transformations 及其在材料工程中的应用。

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, 7. 714-723 (1998)

T.Tamiya等人：“通过电子显微镜对Ti_ 50 Ni_ 48 Fe_2合金中R相转变的原位观察”Materials Trans.，JIM。