超塑性变形晶界效应研究综述

自1934年超塑性现象被发现, 一直以其特殊的塑性变形机制而备受关注.本文以对超塑性变形晶界研究为主线, 从力学角度总结了近年来研究成果. 包括: 基于晶界拓扑构造、统计规律以及能量耗散的力学模型; 论述了由孔洞损伤导致的超塑性沿晶破坏、晶界结构演化与宏观率敏感性之间的关系; 列举了考虑晶界效应的典型超塑性数值模型; 总结并讨论了晶界滑移定量表征的重要实验手段, 指出超塑性研究中需进一步拓展的领域: 多尺度耦合的超塑性力学、材料制备及组合工艺中利用超塑性. 

A REVIEW ON GRAIN BOUNDARY EFFECTS IN SUPERPLASTICITY

Since superplasticity was discovered in 1934, much attention has been paid to its special deformation mechanisms. In this paper, with the investigation on grain boundaries being taken as the main thread, some new developments are summarized from a viewpoint of mechanics, including the models based on the grain boundary topological structure, statistical law and energy dissipation theory. Superplastic intergranular fracture due to the grain boundary void damage and relationships between grain boundary structure changes and macroscopic rate-sensitivity are addressed. Typical numerical models for superplastic deformation simulations are enumerated, with considerations of grain boundary effects. Some important experimental methods measuring the grain boundary sliding are reviewed and discussed. Finally, we suggest some future directions in superplasticity, including multi-scale coupled superplastic mechanics, applications of superplastic properties in material preparations and SPF/DB fabrication process.