Effects of Friction Stir Process and Stabilizing Heat Treatment on the Tensile and Punch-Shear Properties of Mg–9Li–2Al–1Zn Magnesium Alloy

Abstract

In this research, Mg–9Li–2Al–1Zn (LAZ-F) magnesium alloy was studied on a friction stir process (LAZ-FSP), and the FSP specimens had stabilized heat treatment (LAZ-FSP-S) to improve the punch-shear properties. LAZ-FSP revealed the network-like structure and particle in the stir zone. Cracks could be found on the subsurface of punch-shear LAZ-F and LAZ-FSP specimens. Notably, specimens with stabilizing heat treatment had no obvious defects on the subsurface after the punch-shear test. It is convincible that stabilizing heat treatment had improved the punch-shear properties of LAZ921. On the other hand, LAZ-FSP shows excellent tensile strength, while LAZ-FSP-S shows a better elongation. Therefore, stabilizing heat treatment at 60°C not only had showed improvements on workability, but also had effectively increased the ductility of magnesium alloy under room temperature.