Detwinning behavior of an extruded AZ31 magnesium alloy during uniaxial compression

Detwinning behavior of an extruded AZ31 magnesium alloy during compression deformation was investigated by means of metallography and X-ray diffraction (XRD), and a detwinning mechanism was suggested. The results show that the fraction of twins increases with increasing strain when the strain is low, but decreases if the strain is higher than about 4%. It indicates that detwinning occurs in the process. The grain rotation theory can be used to explain this peculiar behavior. The rotation of matrix at higher strain results in the change of stress state of {10 1̄2} tension twins activated at lower strain, and the twinned portions are capable of re-twinning, which causes the re-orientation of the twinned-portions.