Metadynamic recrystallization behavior of 5083 aluminum alloy under double-pass compression and stress relaxation tests

Abstract The static softening behavior of A5083 aluminum alloy was studied through two thermomechanical tests, namely double-pass compression test and stress relaxation test. Metadynamic recrystallization and the further conventional static recrystallization cannot achieve complete recrystallization, which means that in the stress relaxation test, the traditional method used to determine the recrystallized fraction is no longer applicable. Hence, a new method is proposed based on the sigmoidal relationship between the relaxation stress and the recrystallized fraction. The order of the effects of the forming parameters on the metadynamic recrystallization, from strong to weak, is as follows: strain rate, temperature, and first-pass strain. External stress plays a significant role in retarding metadynamic recrystallization, thereby amplifying the effects of the forming parameters on the metadynamic recrystallization. Interestingly, metadynamic recrystallization, which is considered to occur immediately, has an incubation time of approximately 1 s in the studied aluminum alloy. The evolution of the microhardness and microstructure studied through microhardness tests and electron backscatter diffraction confirmed these conclusions. In addition, the phenomena of stress hardening and yield stress drop, caused by strain aging, were observed only under special experimental conditions.