Effect of shear stress and compressive stress deformation on LPSO phase kink behavior of Mg-Gd-Y-Zn-Zr alloy

Abstract

Using torsion and compression experiments, the kink behavior of the long period stacking ordered (LPSO) phase under different stress deformation of the Mg-13Gd-4Y-2Zn-0.5Zr alloy were studied. The results show that different stress states have different effects on the kink of LPSO phase. The grain deformation of the shear stress deformed (SSD) alloy is relatively weak, where LPSO phases are mostly C-shaped or S-shaped kinks. The kink forms can be divided into parallel kinks and angular kinks. The grains of compressive stress deformed (CSD) alloy are significantly elongated and perpendicular to the compression direction, in which occur more Z-shaped zigzag kinks. The kink angle and kink times of the shear stress deformed alloy are small, while the relative kink width is larger. There are large number kink bands during compressive stress deformation, almost all of which are distributed in perpendicular to the compression direction. The difference in the kink behavior is due to the non-basal slip of SSD is easy to active, while in the CSD alloy, the non-basal slip is relatively difficult to active, resulting in more dislocation pile-up. Different forms of kinks can release stress concentration, and all of kinks make the grains deflect in the direction with higher non-basal slip schmid factor.

Keywords

• LPSO
• Mg-RE
• microstructure
• kink