Warm deformation mechanism of hot-rolled Mg alloy
(College of Materials Science and Engineering, Hunan University, Changsha 410082, China)
Abstract: Tension attachment of high temperature microscopy was proposed to research the microstructure evolution and plastic behavior of AZ31 magnesium alloy in a temperature range of 473-523 K and a load range of 80-160 N. Transmission electron microscopy(TEM) was utilized to observe the morphology of twins after deformation process. The results show that as Zener- Hollomon parameter Z increases (temperature falls, strain rate rises), the peak stress obviously increases, while the ductility tends to become worse. A great amount of twins can be found at moderate temperatures. Therefore, basal slip, a+c non-basal slipping and twinning are considered the dominant mechanisms at moderate temperatures. Some DRXed grains can be observed in the twinned regions and grain boundaries, suggesting both twinning-induced DRX and continuous DRX occurs in the deformation process.
Key words: magnesium alloy; twinning; high temperature microscopy; microstructure