Compressive stress and shear stress on the deformation mechanism of Mg-13Gd-4Y–2Zn-0.5Zr alloy at different deformation temperatures

At present, alloys are affected by various stress states during their deformation process. Various stresses can facilitate alloy deformation at the same time, and the influence of these stresses on material deformation is difficult to clarify. It is essential to clarify the difference in the deformation mechanism of an alloy in a single stress state In this work, the internal deformation mechanism of the Mg-13Gd-4Y–2Zn-0.5Zr alloy under two stress states at different deformation temperatures was studied by compression and torsion experiments. The results show that the grain is slightly deformed under shear stress deformation, and the long period stacking ordered (LPSO) phases of different forms show smaller kink angles, fewer kink times, and larger relative width ratios of the kink bands. Under compressive stress deformation, the grain is obviously compressed along the CD direction and presents a streamline, and the LPSO phase is severely kinked. Different stress states have a great influence on dislocation slip, and the shear stress state can easily provoke the initiation of non-basal slip. Non-basal slip has difficulty starting under compressive stress, which leads to dislocation packing. The dynamic recrystallization (DRX) fraction of compressive stress deformation is higher than that of shear stress deformation. Shear and compressive stress deformation alloys activate different kinds of twinning. In shear stress deformed alloys, tensile twins usually occur in grains with a small basal slip Schmid factor (SF). However, compression twins are activated in the compressive stress deformation alloy and occur in grains with larger SF values. When the slip is not fully coordinated with the deformation, kinking and twining occur to coordinate the deformation.