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

为了通过控制材料的微观结构来获得高性能材料，将微观结构及其在宏观变形下的演变的计算策略推广到目前的问题。随后，将该方法应用于具有微观结构的材料的宏观特性评价问题。以下是主要结果。(1)对采用本征应变场的细分法进行了改进，得到了精确的解，并将该方法用于评价短纤维增强复合材料的整体性能，明确了适当的增强排列，以实现复合材料所期望的特性特征。(2)采用基于基体材料塑性变形应变梯度本构方程的计算模型和均质化方法，阐明了增强颗粒的体积分数、尺寸和分布模式以及颗粒分布方向相对于外加应力对复合材料宏观特性的影响。塑性范围内变形抗力增大的主要机制是基体材料的高应变梯度，应变梯度随颗粒间距的减小而增大。这些都提出了提高变形抗力的方法。(3)建立了基于晶体塑性理论的本构方程三维均匀化方法，探讨了γ′相体积分数和γ′/γ相结晶方向差异对合金特征特征的影响。在微观尺度上，由于γ′相析出引起的变形不均匀，应变分布对其性能有显著影响

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