针对异质金属摩擦焊界面冶金结合机制及接头亚稳态组织形成过程，开展摩擦焊接头大变形热力耦合过程中异质界面的原子超扩散研究，并借助有效温度的概念，揭示异质摩擦焊接头形成过程中的非平衡组织演变机理。以摩擦焊大变形物理模拟实验为基础，开展不同异质纯金属(互溶Cu-Ni和不相溶Cu-Fe)扩散偶在摩擦焊变形过程中界面原子超扩散规律研究，建立异质摩擦焊接头原子超扩散系数的唯象表征；分析变形激活扩散与热激活扩散的耦合特征，阐明摩擦焊热力耦合外场作用下原子超扩散产生的微观机制；分析变形激活扩散对非平衡组织演变过程的影响，构建摩擦焊接头体系有效温度模型，并研究其用于摩擦焊接头非平衡组织分析的物理机制；最终，以有效温度为主要参量，从热力学角度分析异质摩擦焊接头形成过程中非平衡组织演变的基本规律。研究结果可为阐明异质摩擦焊界面冶金结合机理提供理论支撑，为摩擦焊变形条件下组织演变过程分析提供新的途径。

To investigate the interfacial metallurgical bonding mechanism and the microstructure formation of the dissimilar friction welding joints, the atomic superdiffusion of heterogeneous interface during the large thermal deformation of friction welding will be studied. The concept of effective temperature will be used to reveal the nonequilibrium microstructure evolution of the dissimilar friction welding joints. Based on the physical simulation experiment of rotary friction welding, the atomic superdiffusion of the dissimilar pure metal (miscible Cu-Ni and immiscible Cu-Fe) will be studied. And the phenomenological characterization of the diffusion coefficient will be established. The coupling mechanism of the deformation activation and the heat activation diffusion will be studied to reveal the physical mechanism of superdiffusion during the friction welding process. The effective temperature model of the dissimilar friction welded joint will be constructed, and its physical mechanism used in the analysis of non-equilibrium microstructure of the friction welded joint will be studied. Finally, the effective temperature, as the main parameter, will be used to perform thermodynamic analysis of the basic law of nonequilibrium microstructure evolution of the dissimilar friction welding joint. Related results can provide theoretical support for the metallurgical theory of heterogeneous metal friction welding, and provide a new way for the analysis of microstructure evolution under friction welding.