Investigation of Martensite Ageing Effect and the Rubber-like Behavior

马氏体时效效应和类橡胶行为的研究

• 批准号: 07455253
• 负责人: OTSUKA Kazuhiro
• 金额: $ 4.86万
• 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 (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455253/
• 关键词: rubber-like behavior; ageing effect; martensite; Au-Cd; Ti-Ni; reverse transformation temperature; martensite ageing; 双晶

The strange phenomenon called "the rubber-like behavior" occurs in the following way. When the alloy is deformed in the martensitic state right after the transformation, it is plastic, while when it is aged in the martensitic state for some time, it becomes pseudoelastic. Although the phenomenon is known for more than 60 years, the origin is still not known yet. To understand the origin and mechanism, the characteristics of the phenomenon was studied in detail by employing various techniques such as tensile tests, DSC,4 circle x-ray diffractometer, internal friction etc. The Au-49.5at%Cd alloy (trigonal martensite) was used mostly, in addition to Au-47.5at%Cd (orthorhombic) and Ti-Ni alloys. Thus, the following basic characteristics were confirmed for this peculiar phenomenon.1) The critical stress for twinning, the Af temperature and Young's modules increase, while the internal friction decreases with ageing.2) The rubber-like behavior is a volume effect rather than a boundary effect. … More 3) The effect of martensite ageing annihilates once the specimen is reverse trasformed to the parent phase.4) The martensite ageing effect is enhanced by the presence of vacancies, and is considered to occur by short range diffusion. i.e.there is no ageing effect in Ti-Ni alloy, where the density of vacancies is very low. The activation energy for the ageing effect was measured to be 0.44eV.5) The average structure and the long range order of a martensite do not change with ageing.Considering these characteristics, most of the 9 models so far proposed for the phenomenon are ruled out, except for the following three models. i) short range order model (Marukawa-Tsuchiya), ii) strain dipole model (T.Suzuki) and iii) vacancy interaction ordering model (Ren and Otsuka, present work). However, all these models have some shortcomings. To get a breakthrough, measurements of defect denities (i.e.the densities of vacancies and anti-structure defects) are very important, and the research for the goal is still intensively continued. We believe the solution for the strange effect will be obtained in the near furture. Less

这种被称为“橡胶样行为”的奇怪现象是以以下方式发生的。当合金在相变后立即处于马氏体状态时，合金具有塑性，而当合金在马氏体状态下时效一段时间后，合金变为假弹性。虽然这种现象已经存在了60多年，但其起源至今仍不清楚。为了了解这一现象的成因和机理，采用了拉伸试验、DSC、4圆x射线衍射仪、内摩擦等多种技术对这一现象的特征进行了详细研究。除Au-47.5at%Cd（正交合金）和Ti-Ni合金外，主要采用Au-49.5at%Cd合金（三角马氏体）。因此，这种奇特现象有以下几个基本特征。1)随着时效的增加，孪晶临界应力、Af温度和杨氏模量增大，而内耗减小。2)类似橡胶的行为是一种体积效应而不是边界效应。一旦试样反向转变为母相，马氏体时效的影响就会消失。(4)空位的存在增强了马氏体时效效应，认为空位的存在是由短程扩散引起的。即在Ti-Ni合金中没有时效效应，其空位密度很低。老化效应的活化能为0.44eV。5)马氏体的平均组织和长程有序不随时效而改变。考虑到这些特点，目前提出的9种模型中，除以下3种模型外，大多数模型都被排除在外。i)短程有序模型（Marukawa-Tsuchiya）， ii)应变偶极子模型（T.Suzuki）和iii)空位相互作用有序模型（Ren和Otsuka，目前的工作）。然而，所有这些模式都有一些缺点。为了取得突破，缺陷密度的测量（即空位和反结构缺陷的密度）是非常重要的，为此目标的研究仍在深入进行。我们相信在不久的将来会找到解决这种奇怪效应的方法。少

项目成果

Y.Murakami: "Internal Friction Measurements for the β_2→ζ_2' (trigonal) Martensitic Transformation and the Ageing Effect in a Au-49.5at% Cd Alloy" Proc.Int.Conf.on Displacive Phase Transformations and Their Applications in Materials Engineering (Urbana).

Y.Murakami：“Au-49.5at% Cd 合金中 β_2→ze_2（三角）马氏体相变和时效效应的内部摩擦测量”Proc.Int.Conf.on 位移相变及其在材料工程中的应用（厄巴纳）。

T.Ohba: "Diffraction Profile Change in Au-Cu-Zn Alloy with Aging" Journal de Physique IV. 1083-1086 (1995)

T.Ohba：“Au-Cu-Zn 合金随老化的衍射剖面变化”Journal de Physique IV。

Y. Murakami: "Study of deformation behaviors associated with ζ′_2-γ′_2 stressinduced martensitic transformations in a Au-49.5at%Cd alloy" Proc.Int.Conf.on Martensitic Transformations(ICOMAT-95), Lausanne. (in press). (1996)

Y. Murakami：“Au-49.5at%Cd 合金中与 ζ′_2-γ′_2 应力诱导马氏体转变相关的变形行为的研究”Proc.Int.Conf.on Martensitic Transformations(ICOMAT-95)，洛桑 (in)。 (1996)

K.Otsuka: "Recent Studies on the β_2→ζ_2' (trigonal) Martensitic Transformation in Au-Cd Alloys" Proc.Int.Conf.on Displacive Phase Transformations and Their Applications in Materials Engineering (Urbana). (in press). (1996)

K.Otsuka：“Au-Cd 合金中 β_2→ze_2（三角）马氏体相变的最新研究”Proc.Int.Conf.on 位移相变及其在材料工程中的应用（Urbana）（出版中）。 ）

M.Kozuma: "Effect of Ageing the R-Phase in Ti-Ni Based Alloys" Proc.Int.Conf.on Displacive Phase Transformation and Their application in Materials Engineering (Urbana, 1996). (in press).

M.Kozuma：“Ti-Ni 基合金中 R 相的时效效应”Proc.Int.Conf.on Displacive Phase Transformation 及其在材料工程中的应用（Urbana，1996）。