Reducing the tension-compression yield asymmetry in a hot-rolled Mg-3Al-1Zn alloy via multidirectional pre-compression

The effect of multidirectional pre-compression on the tension-compression asymmetry in a hot-rolled Mg-3Al-1Zn alloy is investigated in the present paper, revealing that the tension-compression asymmetry is greatly decreased via multidirectional pre-compression. The analysis of deformation behaviors through in situ EBSD observation demonstrates that the {101-2}-{101-2} double twins could be generated in the previously formed {101-2} twins and the existing {101-2}-{101-2} double twins could be de-twinned to the {101-2} twins under favorable orientations. De-twinning could happen through the movement of the boundaries and the nucleation of new lamellas. In addition, the {101-2}-{101-2}-{101-2} twins are difficult to occur in narrow {101-2}-{101-2} twins under low stresses, causing de-twinning to also happen in the double twins even though their orientation facilitates the activation of {101-2}-{101-2}-{101-2} twinning.