Al-Zn-Mg合金超低温高速大变形中超细晶组织演化行为的研究

Microstructural Evolution of Ultrafine-Grained Al-Zn-Mg Alloy during High Speed and Large Plastic Deformation at Cryogenic Temperature

摘要:

利用透射电子显微镜研究了Al—Zn-Mg铝合金在低温(液氮)高速多向大变形条件下的显微组织演化，分析了合金在不同变形条件下的变形及组织形貌特征，讨论了低温及几何动态再结晶对显微组织演化过程的影响。结果表明：在超低温、高速、大形变量、约束变形条件下，7075铝合金能够不经过退火实现连续的大变形而不会失效，并且获得了均匀的超细晶组织，晶粒尺寸小于200nm；超细晶组织随着变形量增加而明显细化，相邻晶粒的取向差增大。

Abstract:

Under constrained condition, severe plastic deformation at high speed can be carried out at extreme low temperature without annealing. Homogeneously Ultrafine-Grained (UFG) 7075 aluminum alloy (e.g. Al-Zn-Mg alloy) with size about 200 nm was fabricated. Evolution of microstructure was studied by transmission electron microcopy (TEM). Different deformations were observed. Factors such as low temperature and dynamic recrystallization contributing to microstructural evolution were discussed.