Improvement of Low Temperature Formability of AZ31 Magnesium Alloy by High Speed Rolling

Abstract

Magnesium alloys have attracted great attention for wide applications as structural materials for automotive industry due to their low density, high specific strength and stiffness, compared to aluminium and steel. Therefore, Mg alloys have potential to reduce the weight of the vehicles and thus to decrease the fuel consumption and CO2 emission. However, the limited formability of Mg alloys at low temperatures, which is owing to the insufficient number of slip systems and the strong basal texture, impedes the applications of the wrought Mg products. In the present study, a high reduction of 72% was achieved at a low temperature of 100 °C by employing high speed rolling (1000 m/min) in single pass. As compared, a low rolling speed of 15 m/min was selected to produce the Mg sheets at the same temperature. The sheet fractured at a reduction of 37% during low speed rolling. Deformation mechanisms of low temperature rolled AZ31 Mg alloy sheets were studied by comparing two significantly different rolling speeds.