Development of the new method to investigate the phase transformations based on the computational scientific approachs.

开发基于计算科学方法研究相变的新方法。

基本信息

批准号：
09242105
负责人：
MIYAZAKI Toru
金额：
$ 39.94万
依托单位：
Nagoya Institute of Technology
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

项目摘要

(1) Computer simulation of the phase decomposition based on the non-linear evolution equation (Miyazaki).The time evolution of the phase decomposition in the real alloy system (such as Al-Zn, Cu-Co, Fe-Mo, Fe-Al-Co, Fe-Cr and III-V compound semiconductor, etc.) was investigated experimentally. The dynamics of the microstructure changes for those alloy systems were simulated on the basis of the Phase-field Method developed by the present research. The morphological feature of the calculated microstructures were in good agreement with the experimental results.(2) Computational analysis of the critical phenomena (Mohri).The susceptibility and relaxation time for the order-disorder phase transition near the transition point were investigated by the Cluster Variation and Path Probability Method, numerically. The susceptibility diverged toward the spinodal disordering temperature when the transition type is first order. It is well known that the critical slowing down will occur at the second order phase transition point. We found that the similar phenomenon will take place even for the first order phase transition by our calculation. The flatness of the free energy at the vicinity of the transition point would be the origin for the phenomena above mentioned.(3) Theoretical investigation for the rubber-like behavior of Martensitic transformation (Ohta).The rubber-like behavior of Martensitic transformation was simulated, successfully. The constitutive equations for the stress and strain field were deduced from the phase field type evolution equations with considering the twin boundary motion. The stress-strain curve and its frequency dependence were predicted by the numerical simulation.

（1）基于非线性演化方程（宫崎）的相分解计算机模拟。真实合金体系（如Al-Zn、Cu-Co、Fe-Mo、Fe- Al-Co、Fe-Cr、III-V族化合物半导体等）进行了实验研究。基于本研究开发的相场方法模拟了这些合金系统的微观结构变化的动态。计算得到的微观结构的形貌特征与实验结果吻合良好。(2)临界现象(Mohri)的计算分析。利用Cluster研究了相变点附近有序-无序相变的敏感性和弛豫时间。数值变异和路径概率方法。当过渡类型为一级时，敏感性向旋节线无序温度发散。众所周知，临界减速将发生在二阶相变点。通过计算我们发现即使是一级相变也会发生类似的现象。转变点附近自由能的平坦性将是上述现象的根源。(3)马氏体相变类橡胶行为的理论研究(Ohta)。马氏体相变类橡胶行为为模拟，成功。由相场型演化方程推导出考虑孪晶边界运动的应力应变场本构方程。通过数值模拟预测了应力-应变曲线及其频率依赖性。