Hot compression behavior and deformation microstructure of Mg-6Zn-1Al-0.3Mn magnesium alloy

The hot compression behavior of a wrought Mg-6Zn-1Al-0.3Mn magnesium alloy was investigated using Gleeble test at 200–400 °C with strain rates ranging from 0.01 to 7 s−1. The true stress-strain curves show that the hot deformation behavior significantly depends on the deformation temperature and strain rate. The calculated hot deformation activation energy Q is 166 kJ/mol with a stress exponent n=5.99, and the constitutive equation is deduced to be ɛ˙=3.16×1013[sinh(0.010σ)]5.99 exp [−1.66×105/(RT)]. Deformation microstructure shows that the incompletely dynamically recrystallized grains can be found at grain boundaries and twins with the strain rates ranging from 0.01 to 1 s−1 at 250 °C, and completely dynamic recrystallization occurs when the temperature is 350 °C or above during hot compression, the size of recrystallized grains decreases with the increment of the strain rate at the same temperature. The relatively suitable deformation condition is considered temperature 330–400 °C and strain rate of 0.01–0.03 s−1, and temperature of 350 °C and strain rate of 1 s−1.