Development of Texture Prediction Technique for Structural Control and High Quality Characteristics of Metallic Materials

金属材料的许多宏观性能在很大程度上取决于多晶集合体中的取向分布，即所谓的“晶体织构”。本研究旨在开发以初始织构为ODF表示的变形织构演化的定量预测方法和PC计算系统。在本研究中，特别考虑了晶界附近的微观应变不均匀，这对变形织构的演化有重要的影响。首先，我们基于“矢量空间法”建立了新的晶体塑性理论，该理论可以唯一地确定与速率无关的晶体的活动滑移速率和合成的晶格自旋。在此基础上，考虑了颗粒间相互作用引起的应变非均质场，利用新的计算方法对变形织构进行了模拟。成功地开发了变形织构预测的数学算法和计算程序。最后，将该计算程序应用于铝合金和IF钢板轧制织构的演变过程。预测结果与实验结果吻合较好。此外，我们所提出的计算系统的实现也被认为适用于通过变形加工来获得高质量特征的织构控制技术。

Many macroscopic properties of metallic materials depend significantly on the orientation distribution in polycrystalline aggregate, so called "crystallographic textures". The present study has been designed to develop the quantitative prediction method and the PC calculation system for deformation texture evolution in the case that the initial texture is given as the representation of ODF. In this study, in particular, the microscopic strain heterogeneity near the grain boundaries, which has an important effect on the deformation texture evolution, is taken into consideration for the calculation of lattice rotation in each crystal.First, we have made the formulation of new crystal plasticity theory, in which the active slip rates and resultant lattice spin in a particular crystallite can be determined uniquely for rate-independent crystals, based on "the vector space method". We further have done the modeling of deformation texture using the new calculation scheme considering strain heterogeneous field due to the grain-to-grain interaction. As the results, the mathematical algorithm and computational procedure have been successfully developed for the deformation texture prediction. Finally, this computational procedure has been applied for the evolution of rolling texture of Al-alloy and IF-steel sheets. The predicted results were reasonable agreements with the experimental ones. Also, the implementations of our proposed computational system are considered to be applicable to the texture control technique for high quality characteristics by means of deformation processing in metallic materials.