The application of the bifurcation theory to the microstructure change and its stability.

分岔理论在微观结构变化及其稳定性中的应用

基本信息

批准号：
02452245
负责人：
MIYAZAKI Toru
金额：
$ 4.35万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Several interesting phenomena for the formation of microstructure have recently been observed when the alloys, ceramics and semiconductors are elastically constrained. Particularly, the extraordinary behavior, in the precipitate coarsening ; deceleration of particle coarsening, stopping the particle coarsening and splitting of a particle into plural small particles are typical examples. These phenomena have theoretically supported by "bifurcation diagram", proposed by us. In the practical point of view, this phenomena imply an existence of non-overaging materials even if heated at high temperature for atom to diffuse. The purpose of the present work is to get a more wide range of experimental examinations and also to give more accurate theoretical back ground.The experimental results obtained for this academic year are written below.(1) Hitherto the splitting of particle was recognized in Ni-base alloys such as Ni-Al, Ni-Si and so on. However, the splitting has first been observed in I … More ron base Fe-Al-Co ternary alloys. This examination fact clearly shows that the splitting of particles is not special but common in the elastically constrained system.(2) In the Fe-Al-Ge system which has a small eigenstrain the precipitates increase their sizes L with aging time t in accordance with LSW theory, that is L=k ・t^<1/3>. In the Fe-Al-V system having a large eigenstrain, however, the uniformalization of particle size and the deceleration of particle coarsening were experimentally recognized. Inevitability of such the characteristic coarsening is theoretically discussed on the basis of the bifurcation diagram.(3) New parameters showing the 3-dimensional distribution of particles are introduced to classify the microstructures(4) In the conventional bifurcation disgrain the microstructure consisting two particles vas adopted as the most simple case of the many body microstructure. In this research, the many body microstructure is taken into the calculation of bifurcation diagram so as to analyze more accurate behavior of the particle coarsening. Less

最近，当合金、陶瓷和半导体受到弹性约束时，观察到了一些有趣的微观结构形成现象，特别是沉淀物粗化、颗粒粗化减速、颗粒粗化停止和颗粒分裂成多个的异常行为。小颗粒是典型的例子。这些现象在理论上得到了我们提出的“分岔图”的支持。从实践的角度来看，这种现象意味着即使在高温下加热也不会过度老化。本工作的目的是为了获得更广泛的实验检验，并提供更准确的理论背景。本学年获得的实验结果写在下面。（1）迄今为止的粒子分裂。在 Ni-Al、Ni-Si 等镍基合金中发现了这种现象，但首先在 I 基 Fe-Al-Co 三元合金中观察到了这种现象。粒子并不特殊，但是(2) 在特征应变较小的 Fe-Al-Ge 系中，根据 LSW 理论，随着时效时间 t，析出物的尺寸 L 增大，即 L=k·t^<1/ 3>然而，在具有大特征应变的Fe-Al-V系中，通过实验认识到颗粒尺寸的均匀化和颗粒粗化的减缓是这种特征粗化的必然性。 (3)引入了显示颗粒三维分布的新参数来对微观结构进行分类(4)在传统的分叉分类中，采用由两个颗粒组成的微观结构作为最简单的情况本研究将多体微观结构纳入分岔图计算中，以更准确地分析颗粒粗化行为。