The mechanical anisotropy of directionally solidified Mg-4 wt.% Zn alloy under compression test

The mechanical anisotropy of directionally solidified Mg-4 wt.% Zn alloy was studied under compression test at room temperature. The results show that directionally solidified Mg-4 wt.% Zn has higher compression strength and work hardening rates when compression axis is parallel to the growth direction, which is mainly due to the formation of {10 (1) over bar2} extension twins. Besides, the microstructural evolution in the process of plastic deformation was also investigated. When the compression axis is parallel to the growth direction, plastic deformation of the alloy starts with multi-slip systems and {10 (1) over bar2} twins are activated as the strain increases. The interactions among the twins, matrix and dislocations result in the occurrence of sub-grains and the fragmentation of columnar grains.