Study of growth twins produced through heat treatment of fine-grained magnesium

This study investigated the microstructural features of magnesium after the fine-grained magnesium sample was heat treated at 400 °C for 2 h. Both fine-grained and heat-treated magnesium samples were observed using the electron backscatter diffraction technique in scanning electron microscopy. The results show that the grains were substantially coarsened, the local strain and the local misorientation was significantly reduced, and a large number of twins were observed in the heat-treated magnesium sample. The misorientation angle analysis determined that the twins were oriented about 86.3° away from the orientation of their corresponding matrices, and the twins were the variants of {1 0 1 ‾ 2} tensile twins. The relative orientation analysis also identified that the fast growth directions of the twins were closely along the <2 1 ‾ 1 ‾ 0> or <1 0 1 ‾ 0> directions in the basal plane. The twins can merge or impinge onto each other. Most boundaries between the twins have the misorientation angle of about 7.4°.