Microstructure and texture evolution in AZ31 magnesium alloy during caliber rolling at different temperatures

摘要

Magnesium alloy AZ31 was caliber rolled at different temperatures viz. 523K, 573K, 623K, 673K and 723K imposing a total cumulative reduction of 92% and a cumulative strain of 2.6. The associated microstructure and texture evolution were studied using Electron Back Scattered Diffraction (EBSD) and X-ray macro-texture observations respectively. Grain refinement was observed in all the caliber rolled bars indicating the occurrence of dynamic recrystallization. Asymmetry parameter and texture index were used to study the evolution of texture. Near doubling of the yield strength at room temperature was observed by caliber rolling at a temperature of 573K. The improvement in mechanical properties was explained on the basis of the fine grain microstructures and suitable development of crystallographic texture. Based on the present study, warm caliber rolling can be used as a good production method for obtaining long bars of high strength magnesium alloy AZ31.