Clarification and Functionalization of Micro -and Mezzo structure near Boundary between Different Phase in Single-crystalline Super Metals

为了通过对材料微观结构的控制来获得高性能的材料，将微观结构与宏观变形引起的微观结构演化联系起来的计算策略推广到目前的问题。随后，该方法已被应用到与具有微结构的材料的宏观特性特征的评价相关的问题。主要结果如下。(1)采用本征应变场的细分方法已被修改，以获得准确的解决方案，该方法已被用来评估短纤维增强复合材料的整体性能，并阐明了适当的增强体的安排，以实现所需的特性功能的复合材料。(2)采用应变梯度本构方程和均匀化方法建立了基体材料塑性变形的计算模型，阐明了增强颗粒的体积分数、尺寸和分布方式以及颗粒分布方向对复合材料宏观特性的影响。在塑性范围内变形阻力增加的主要机制是基体材料中的高应变梯度，其随着颗粒之间的距离的减小而增加。这些都提示了提高变形行为抗力的途径。(3)采用基于晶体塑性理论的本构方程，建立了三维均匀化方法，研究了γ ′相体积分数和γ ′/γ相晶向差异对合金特性的影响。在微观尺度上，γ ′相析出引起的不均匀变形引起的应变分布对其影响很大

In order to obtain the high performance material through the control of the microstructure of the materials the computational strategies to relate the microstructure and its evolution due to macroscopic deformation has been generalized to adopt the present problems. Subsequently, the methods have been applied to the problems associated with the evaluation of the macroscopic characteristic feature of the material with microstructures. The followings are the main results.(1) Subdivisions Method employing the eigen strain fields has been modified to obtain an accurate solution and the method has been used to evaluate the overall properties of short fiber reinforced composites and clarified the proper arrangement of reinforcement to realize the desired characteristic feature of the composite.(2) With a computational model employing the strain gradient constitutive equation for plastic deformation of the matrix material and a homogenization method, the effects of the volume fraction, size and distribution pattern of reinforced particles and direction of particle distribution with respect to applied stress on the macroscopic characteristic feature of the composites were clarified. The main mechanism of the increase of the deformation resistance in the plastic range is the high strain gradient in the matrix material, which increases with decreasing distance between the particles. These all suggest the way of an enhancement of resistance of the deformation behavior.(3) A three dimensional homogenization method employing the constitutive equation based on the crystal plasticity theory has been developed and the effect of the volume fraction of γ´ phase and the difference of crystalline directions of γ'/γ phases on the characteristic feature of the alloy. It is significantly affected by the strain distribution due to the inhomogeneous deformation induced by the γ´ phase precipitation on a microscopic scale