The Application of the Bifurcation Theory to the Stability of Microstructure and the Improvement of the Superalloys.

分岔理论在微观组织稳定性及高温合金改进中的应用。

基本信息

批准号：
07455280
负责人：
MIYAZAKI Toru
金额：
$ 4.86万
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 (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-07455280/
关键词：
Elastic interaction Bifurcation theory Ostwald ripening Elastic constraint Interfacial energy Particle size distribution Stability of microstructure Microstructure change

项目摘要

Several interesting phenomena for the formation of microstructure have recently been observed when the materials are elastically constrained. Particularly, the extraordinary behavior in the precipitate coarsening ; deceleration of particle coarsening and splitting of a particle into small ones are typical examples. These phenomena have theoretically supported by "bifurcation theory". In the practical point of view, these phenomena predict an existence of non-over aging materials. The purpose of the present work is to get more wide range information for these phenomena experimentally, and also to give more accurate theoretical background. The results obtained are as follows.(1) Splitting of a particle was newly recognized in Ni-Mo and Fe-Al-Co alloy systems. However, the shapechanging rate of split particles in Fe-Al-Co was remarkably fast. Results from the energetic estimation for the sequence of the particle splitting, the splitting path experimentally observed was consistent with min … More imum-energy path predicted by the theoretical calculation(2) We proposed a new experimental method to investigate the composition dependent phenomena in materials science based on the observation of microstructure changes in a continuous composition gradient field. Utilizing this new method, the equilibrium compositions at the interface of precipitate/matrix could experimentally be obtained for various particle sizes, and thus the Gibbs-Thomson's relation, which is the fundamental low in the precipitates coarsening, was verified experimentally.(3) A new calculation method for the nonlinear diffusion equation was proposed, where the composition dependencies of atomic interaction energy, elasticity and mobility of atoms were taken into account so as to be able to calculate the phase decomposition in the real alloy system. The two dimensional simulations were performed for the phase decomposition in the Fe-Mo binary system. The microstructures calculated were well coincident with experimental facts, and typical features in the strain-induced microstructure changes were successfully calculated. Less

最近，当材料受到弹性约束时，最近观察到了微观结构形成的几种有趣现象。特别是，珍贵的浓缩行为的非凡行为；粒子将粒子变质和分裂成小的减速是典型的例子。这些现象通过“分叉理论”具有理论上的支持。从实际的角度来看，这些现象预测了非衰老材料的存在。本工作的目的是在实验中获取这些现象的更广泛的信息，并提供更准确的理论背景。获得的结果如下。（1）在Ni-MO和Fe-Al-CO合金系统中新认识到粒子的分裂。然而，fe-al-Co中分裂颗粒的变形速率非常快。从颗粒分裂序列的能量估计的结果，实验观察到的分裂路径与最小值一致……由理论计算预测的更多iMum-Energy路径（2）我们提出了一种新的实验方法，以研究基于持续组合梯度的微结构变化的材料科学的组成依赖性现象。 Utilizing this new method, the equivalent compositions at the interface of precious/matrix could experimentally be obtained for various particle sizes, and thus the Gibbs-Thomson's relationship, which is the fundamental low in the Precipitates coarsening, was verified experimentally.(3) A new calculation method for the nonlinear diffusion equation was proposed, where the composition dependencies of atomic interaction energy, elasticity and mobility of考虑了原子，以便能够计算实际合金系统中的相分解。对Fe-MO二元系统中的相分解进行了两个维模拟。计算得出的微观结构与实验事实非常吻合，并且成功计算了应变引起的微观结构变化的典型特征。较少的