Strengthening Mg-8Li-3Al-2Zn-1Gd-0.2Zr alloy by combining hot extrusion and cold rolling

The microstructure, texture, and mechanical properties of as-extruded and cold-rolled Mg-8Li-3Al-2Zn-1Gd0.2Zr (LAZ832-1Gd-0.2Zr) alloys were investigated with the aim of strengthening the alloy by combining hot extrusion and cold rolling. Cold rolling does not change the phase composition of as-extruded LAZ832-1Gd-0.2Zr alloy, but introduces a larger number of dislocations and twins into alloy matrix. Cold rolling leads to the weakening of the original {0001} basal and {1120}-{0110} prismatic textures in alpha-Mg matrix, as well as the alpha and gamma fiber textures in beta-Li matrix. But new slip systems that are favorable for cold rolling are activated, resulting in the formation of {0338} pyramidal and new prismatic ({1120}< 1014 > and {1010}< 21110 >) texture components. Cold rolling further strengthens LAZ832-1Gd-0.2Zr alloy on the basis of hot extrusion, mainly through work hardening effect caused by introducing a large number of dislocations into alpha-Mg matrix. When the rolling reduction is 45%, the yield strength and tensile strength of LAZ832-1Gd-0.2Zr alloy are increased to 269.8 +/- 4.0 and 308.6 +/- 4.1 MPa, respectively, and the elongation is higher than 15%.