The high temperature flow behavior modeling of AZ81 magnesium alloy considering strain effects

摘要

In the field of deformation process modeling, constitutive equations are invariably used as a calculation basis to estimate the materials flow responses. Accordingly, in the present study, a constitutive analysis has been conducted on the AZ81 magnesium alloy employing experimental stress-strain data obtained from isothermal hot compression tests. These tests had been done in the temperature range of 250-450℃ under strain rates of 0.003, 0.03 and 0.3 s~(-1). The effects of the temperature and strain rate on hot deformation behavior have been expressed in terms of an exponent-type Zener-Hollomon equation. Furthermore, the influence of strain has been included in the constitutive equation by considering its effect on different material constants. Consequently, a model to predict the high-temperature flow behavior of AZ81 magnesium alloy has been established. The true stress-true strain curves predicted by the extracted model are in good agreement with the experimental results, thereby confirming the validity of the developed constitutive relation.