Cu/Nb复合材料塑性行为及内在位错机理研究

由于兼具优异的力学和电学性能，铜/铌微复合材料在脉冲强磁场磁体绕组线圈、核辐照环境和武器装甲领域都有着广泛的应用。其突出的综合性能来源于其独特的多层级多尺度微结构和多类型界面形式。本项目以该材料在不同应变率和不同温度条件下塑性响应、应变率敏感性及其内在位错机理为核心问题；以“多层级材料微结构”—“位错微结构”—“多类型界面形式”—“多变形机制（跨机制）” —“铜/铌复合材料循环行为和率敏感相关性”之间的相互关联为切入点；以宏细观实验验证和多尺度模拟为手段；首先，探讨铜/铌微复合材料不同各层级微结构下各自独立的应力/应变响应、尺度效应和不同内在位错机理；其次，基于分层均匀化方法升尺度地研究多层级材料/位错微结构和多类型界面对该材料总体塑性行为的影响；最后，深入揭示加载条件、环境温度及其它外部条件（如辐照）的作用，为铜/铌复合材料强度安全分析、寿命评估及其进一步优化设计提供理论基础和技术。

Due to its excellent mechanical and electrical properties, the Cu/Nb microcomposite has been widely used in pulsed strong magnet winding coil, nuclear environment and armor of defense field. Its extraordinary behaviors come from its special hierarchical microstructure and intrinsic multi-interfaces. In this project, we focus on the plastic behaviors of this composite under different loading rates and temperatures, trying to clear the relations between hierarchical material microstructures, complex dislocation microstructures, multiple kinds of interfaces, multiple deformation mechanisms and plastic responses of this material. By microscopic and macroscopic experiments and multi-scale modeling, the mechanical responses of different microstructures at different size scales, size effect and their different dislocation mechanisms are investigated first. Then, basing on the mean-field analytical methods, the overall plastic response of this microcomposite and its dependency on hierarchical material and dislocation structures are studied systematically. Finally, the influence of loading condition, environmental temperature and other conditions (such as irradiation) on the plastic behaviors is taken into account carefully. All these works tend to provide scientific and technical supports for the mechanical analysis and further optimized design of Cu/Nb microcomposites