Effects of strain rate and temperature on microstructure and texture for AZ31 during uniaxial compression

In order to investigate the effects of strain rate and temperature on the microstructure and texture evolution during warm deformation of wrought Mg alloy, AZ31 extruded rods were cut into cylinder samples with the dimension of d8 mmx12 mm. The samples were compressed using a Gleeble 1500D thermo-mechanical simulation machine at various strain rates (0.001, 0.01, 0.1, 1 and 5 s(-1)) and various temperatures (300, 350, 400 and 450 degrees C). The microstructure and texture of the compressed samples at the same strain under different deformation conditions were studied and compared by electron backscatter diffraction (EBSD) in scanning electron microscope (SEM). The results show that the size of recrystallized grains in the deformed samples generally increases with the decrease of strain rate and the increase of temperature. After 50% reduction, most basal planes are aligned perpendicular to the compression direction at relatively high strain rate (>0.01 s(-1)) or low temperature (<350 degrees C). The optimized strain rate is 0.1 s(-1) for uniaxial compression at 300 degrees C, which produces about 80% of small grains (<5 mu m).