Strengthening Mg–8Li–3Al–2Zn-1Gd-0.2Zr alloy by combining hot extrusion and cold rolling
Jian Ren, Hao Meng, Mingjun Yang, Richu Wang, Chaoqun Peng, Yuehua Sun, Yanning Chen, Kang Yang, Guangsheng Song
Abstract
The microstructure, texture, and mechanical properties of as-extruded and cold-rolled Mg–8Li–3Al–2Zn-1Gd-0.2Zr (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 {112‾0}-{011‾0} prismatic textures in α-Mg matrix, as well as the α and γ fiber textures in β-Li matrix. But new slip systems that are favorable for cold rolling are activated, resulting in the formation of {033‾8} pyramidal and new prismatic ({112‾0}⟨101‾4⟩ and {101‾0}⟨21‾1‾10⟩) 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 α-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%.