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

当合金、陶瓷和半导体材料受到弹性约束时，最近观察到了一些有趣的微结构形成现象。特别地，沉淀物粗化中的异常行为;颗粒粗化的减速、颗粒粗化的停止和颗粒分裂成多个小颗粒是典型的例子。我们提出的“分岔图”从理论上支持了这些现象。从实际的角度来看。这种现象意味着即使在高温下加热原子扩散也能得到非过时效功。本工作的目的是为了得到更广泛的实验检验，并提供更精确的理论背景。（1）在Ni-Al、Ni-Si、Fe-Al-Co等镍基和铁基合金中，粒子的分裂行为较明显，但在Ni-Al、Ni-Si、Fe-Al-Co等合金中，粒子的分裂行为较明显。 ...更多信息 镍基合金与铁基合金的抗拉强度不同。在铁基合金中，分裂粒子的形状变化速度非常快。(2)In实验证实了Fe-Si-V系具有较大的本征应变、颗粒尺寸均匀化、颗粒粗化速度减慢和颗粒定向排列<100>等特点。特别是这些行为变得占主导地位的析出物的体积分数增加。在分岔图上从理论上讨论了这种特征粗化的必然性。(3)计算的沉淀形核动力学路径与我们提出的体系自由能理论预测的最小能量路径一致。这一结果表明，即使在相分解的早期阶段，能量分析也是非常有用的。因此，我们在能量估计的基础上计算了粒子粗化的时间发展。通过计算，得到了弹性约束系统中颗粒粗化的更精确的行为。少

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-over ageing work is to get 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 results obtained for this academic years are as follows.(1)Hitherto the splitting of a particle was recognized in Ni-base and Iron-base alloys such as Ni-A1, Ni-Si, Fe-A1-Co and so on. However, the splitting behavior bet … More ween the Ni-base alloys and Iron-base ones was different. The shape changing rate of splitted particles was remarkably fast in Iron base alloys.(2)In the Fe-Si-V system which has a large eigenstrain, the uniformalization of particle size, the deceleration of particle coarsening and particle alignment to <100> direction were experimentally recognized. Especially these behaviors become dominant as the volume fraction of precipitates increase. Inevitability of such the characteristic coarsening is theoretically discussed on the bifurcation diagram.(3) Kinetic path calculated for the precipitate nucleation process was consistent with minimum-energy path predicted by the theory of the system free energy proposed by us. This result indicates that the energy analysis is very useful even for the early stage of the phase decomposition. Therefore we calculated the time developmence of particle coarsening on the base of the energetic estimation. As the calculation results, more accurate behavior of the particle coarsening in elastically constrained systems is obtained. Less