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 {10 (1) over bar2}-{10 (1) over bar2} double twins could be generated in the previously formed {10 (1) over bar2} twins and the existing {10 (1) over bar2}-{10 (1) over bar2} double twins could be de-twinned to the {10 (1) over bar2} twins under favorable orientations. De-twinning could happen through the movement of the boundaries and the nucleation of new lamellas. In addition, the {10 (1) over bar2}-{10 (1) over bar2}-{1012} twins are difficult to occur in narrow {10 (1) over bar2}-{10 (1) over bar2} twins under low stresses, causing de-twinning to also happen in the double twins even though their orientation facilitates the activation of {10 (1) over bar2}-{10 (1) over bar2}-{10 (1) over bar2} twinning. (C) 2012 Elsevier B.V. All rights reserved.