面向再结晶织构控制的金属晶内剪切带行为全谱描述与设计研究

In-grain shear band is one kind of common localized deformation microstructures in rolled metal sheets, which has a significant and even determining role in recrystallization texture development. However, the literatures are basically restricted to the qualitative description on shear banding phenomena. In the present project, with emphasis on body-centered cubic Fe-Si alloys, the in-grain shear banding behavior is to be deeply studied aiming at recrystallization texture control. The microscopic mechanism for in-grain shear banding and the evolution rule of crystal orientation and strain-stored energy within shear bands will be clarified. The dependences of in-grain shear banding behavior on initial grain orientation and rolling temperature will further be figured out. The Fourier series using generalized spherical harmonic functions is first proposed to represent shear banding behavior in the world, by which the spectral quantitative description on in-grain shear banding behavior, i.e. shear band characteristic distribution function, is to be established. Accordingly, the precise design of in-grain shear banding behavior can be realized for recrystallization texture control. The research achievements are helpful to break through the conventional texture design mode, and provide a theoretical basis for developing advanced materials and upgrading traditional materials.

晶内剪切带是金属轧制时形成的一种常见局域化形变微结构，对再结晶织构有显著甚至决定性影响，现有研究集中于对剪切带现象的定性描述。本项目以体心立方（BCC）结构的Fe-Si合金为主要材料，深入开展面向再结晶织构控制的晶内剪切带行为研究。揭示晶内剪切带形成与发展的微观机制以及剪切带内部取向和储能的演变规律，阐明晶内剪切带行为对初始晶粒取向和轧制温度的依赖性；在国际上首次提出以球谐函数级数表征剪切带行为，据此建立晶内剪切带行为的全谱定量描述，即剪切带特征分布函数，从而实现面向再结晶织构控制的晶内剪切带行为设计。研究成果有助于突破材料织构的传统设计模式，为新材料研制和传统材料高性能化提供理论支撑。

织构优化控制已成为充分利用各向异性开发高性能材料的重要方向。晶内剪切带作为常见局域变形组织，强烈影响金属板带再结晶织构。本项目以BCC结构金属材料为重点，采用实验和晶体塑性模拟相结合，阐明了晶内剪切带行为的微观机制及内部取向和储能演变规律，揭示了剪切带行为与外部参数（初始晶粒取向、轧制温度及压下率）间的定量关系。提出了晶内剪切带行为的全谱描述方法，建立了基于剪切带设计的再结晶织构控制模型。研究成果为高端金属材料的织构控制提供支撑，成功研制出国际首发的取向硅钢新产品并在重大工程中获得应用。