CuAlNi合金中相变波与马氏体微结构的交互激励机制研究

项目名称： CuAlNi合金中相变波与马氏体微结构的交互激励机制研究

项目编号： No.11272098

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 甄玉宝

作者单位： 哈尔滨工业大学

项目金额： 78万元

中文摘要： 马氏体相变具有重要的科学研究和工业应用价值，但关于其为何发生、如何发生等相变机理方面的基础问题目前还远不清楚。本项目针对CuAlNi三元形状记忆合金，首先论证了其结构存在的内禀不稳定性，并基于它的各向异性激发合理地解释了惯习面的形成。项目从动力学角度提出新的相变机理，即：相变波携带应变扰动克服相变能垒开启相变，同时通过应力波场动态地改变相变能垒，造成相变波与马氏体微结构发生渐次复杂的交互激励，最后形成自协调的马氏体微结构和各类相变晶体学关系。项目拟先通过大规模分子动力学模拟在原子尺度上确定相变能垒及其对温度、成分和应力环境的依赖关系，并由统计计算提取连续意义下的力学量，得到宏观相变本构关系。然后将其与波动方程耦合，应用有限差分法对相变进程进行数值模拟。最后拟对马氏体相变开展声发射实验研究，结合数值模拟对相变声发射信号进行反演，验证所提相变机理。该项研究将推进对马氏体相变机理的理解。

中文关键词： 马氏体相变；相变波；微结构；原子模拟；松弛弹性模量

英文摘要： Martensitic transformation is of great scientific and engineering importance. However, fundamental problems related to how and why it happens still remain to be answered. Using the CuAlNi shape memory ternary alloy as a modeling material, the current project shows first its intrinsic crystalline instability and then explains how the habit planes form by its anisotropic exciting. Based on a dynamical viewpoint a new martensitic transformation model is proposed, that is, the transformation waves carry the strain disturbance to overcome the transformation barrier and excite the transformation, while the barrier is dynamically altered by the associated elastic stress field. This leads to complicated interactive excitations between the transformation waves and martensitic microstructures, resulting the self-accommodated martensitic microstructures and all crystalline relations. The transformation barrier and its dependence on temperature, composition and local stress environment will be studied first by large-scale molecular dynamics simulations. The macro transformation constitutive relation is then obtained by extracting the mechanics quantities in continuum sense statistically from the atomistic calculations. This constitutive relation, when coupled to the wave equation, enables the tracking of martensitic tra

英文关键词： martensitic transformation；phase transformation wave；microstructure；atomistic simulations；relaxed elastic constants