剧烈塑性变形制备的金属材料失效机理和稳态研究

剧烈塑性变形技术及其制备的多尺度结构金属得到了广泛的研究和关注，但关于剧烈塑性变形的失效、制备金属的力学性能优化极限、梯度纳米结构金属的结构与性能关系以及微结构可控制备方面仍存在诸多挑战和机遇。本项目拟开展以下研究：（1）金属材料在剧烈塑性变形中的失效问题，建立断裂轨迹面描述等效断裂塑性应变和应力状态之间的关系；（2）金属材料在剧烈塑性变形中的稳态力学性能，以及稳态微结构和力学性能的温度和应变率依赖性；（3）梯度纳米结构金属各尺度单元塑性变形的物理机制及各尺度单元之间的协同作用机制，发展基于微结构演化的塑性本构理论揭示结构分布和力学性能之间的定量关系。本项目的研究成果将为实现金属微观结构的可控制备提供支撑和指导。

Severe plastic deformation (SPD) technology and the multiscale structured metals prepared by SPD have received extensive attention. However, there are still many challenges and opportunities regarding the failure of metals processed by SPD, the optimization limit of the mechanical properties of SPD processed metals, the relationship between structure and property of the gradient nanostructured metals, and the controllable microstructure processing. This project intends to carry out the following researches: (1) study the failure of metals processed by SPD and establish fracture locus to describe the relationship between the equivalent fracture plastic strain and stress state; (2) investigate the steady-state mechanical properties of SPD processed metals, and the temperature and strain rate dependence of the steady-state microstructure and mechanical properties; (3) reveal the physical mechanisms underlying the plastic behaviors of multiscale unit of gradient nanostructured metal, the interaction mechanisms between multiscale units, and then develop the mechanism-based constitutive relation to reveal quantitative relationship between the gradient structure and mechanical properties. This project will provide guidance for realizing controllable preparation of the microstructure of metallic materials.