The role of long-period stacking ordered phases in the deformation behavior of a strong textured Mg-Zn-Gd-Y-Zr alloy sheet processed by hot extrusion

摘要

In this work, deformation behavior of an extruded Mg-Zn-Gd-Y-Zr alloy sheet, including mechanical anisotropy and tension-compression asymmetry, were investigated by conducting tension and compression experiments along different directions. Coupling with the strong texture, the role of long-period stacking ordered (LPSO) phases in the deformation behavior was analyzed based on the microscopic plastic deformation theory. The results showed that LPSO phases with different morphologies played different roles in deformation behavior of the strong textured Mg-Zn-Gd-Y-Zr alloy sheet: (i) the irregular-shaped LPSO phases distributed along extrusion direction (ED) brought anisotropic fiber reinforcement and exacerbated the mechanical anisotropy; (ii) the needle-like LPSO phases filled in the grain interior hindered the propagation of twinning boundaries and decreased the tension-compression asymmetry. The results may provide valuable references for the manufacturing of large size Mg/LPSO alloys with low mechanical anisotropy and tension-compression asymmetry, hence making them better to meet the growing need of engineering application.