Effect of rolling temperature on the AZ31B magnesium alloy microstructure

The influence of rolling temperature and the effect of strain rate on the microstructure of AZ31B Mg alloy were determined in order to improve its formability. A plate of AZ31 alloy was found to be sensitive to strain rate at high temperature and anisotropy was adversely impacted in cold rolling sheets. Thus, AZ31B has better workability within the temperature range of 200 to 250 °C, due to the grain refinement, caused by recovery and dynamic recrystallization. The effect of rolling temperature was studied on recrystallized sheets (2 mm in thickness) which were deformed by rolling at different temperatures (25, 100, 200 and 250 °C) and the effect of strain rates was evaluated on two different rolling speed (10 and 20 rpm). The microstructural characterization was achieved using several complementary techniques of microstructural analysis, such as optical microscopy, scanning electron microscopy, X-ray analysis by energy dispersive, X-ray diffraction and microhardness.