Characteristics of magnesium AZ31 alloys subjected to high speed rolling

Abstract

Magnesium AZ31 alloy sheets were rolled at a high (1000m/min) and a low (15m/min) rolling speed. The microstructure and texture evolution were tracked using optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) techniques. At 100°C, a total reduction of 72% was achieved in one pass at the high rolling speed, while the sheet fractured at a reduction of only 37% during low speed rolling. In the former case, dynamic recrystallization was observed to be well under way at a reduction of 49% and full recrystallization was achieved at a reduction of 72%. For a given reduction, the maximum intensity of the basal texture is weaker after high speed rolling than after low speed rolling. The far better rollability achieved during high speed rolling is attributed to the activation of <c+a> slip and dynamic recrystallization at the higher temperatures developed; the weaker texture is due to the activation of a larger number of twinning and slip systems.