Abstract
Uniaxial tension tests were performed on fine-grain Al-Mg alloy (5083-O) sheets at various forming speeds (5.6×(10)^<-5>S^<-1> to 5.3×(10)^<-1>S^<-1>) at elevated temperatures (473 ∿ 623K). From the tests, it was found that the tensile flow stress is strongly influenced by forming speed and temperature. In order to describe such rate-and temperature-dependent stress-strain responses, a viscoplastic constitutive model is presented. In the mode, we assume that the viscoplastic strain rate consists of two components due to the grain-boundary sliding superplasticity and the ordinary viscoplasticity. The predicted stress-strain responses by this constitutive model are in good agreement with the corresponding experimental results.
