Deformation Behaviour of AZ31 Magnesium Alloy Sheets Produced By Twin-Roll Casting and Sequential Hot Rolling

AZ31 alloy sheets were produced by twin-roll casting (TRC) and sequential hot rolling. Uniaxial tensile tests were used to evaluate the deformation properties of the AZ31 alloy at a strain rate of 7x10(-4)s(-1) and a temperature range from room temperature to 400 degrees C. The microstructure evolution and fracture behaviour were observed by optical microscopy and scanning electronic microscope. The results show that the elongation of the AZ31 alloy increases with increasing temperature at a strain rate of 7x10(-4)s(-1). The AZ31 alloy begins to exhibit superplasticity at 300 degrees C. The elongation of 497.8% is achieved at 400 degrees C. The deformation of the AZ31 alloy at low temperature is controlled by dislocation motion, and with increasing temperature (above 300 degrees C), grain boundary sliding (GBS) begins to play a dominant role during superplastic deformation.