Influence of rolling temperature on the microstructure and mechanical properties of Mg-Gd-Y-Zn-Zr alloy sheets

The extruded Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt%) alloy were subjected to large-strain hot rolling with different final rolling temperatures. The microstructural evolution and mechanical properties of the sheets were investigated. The microstructure became homogeneous after hot rolling process and long period stacking ordered (LPSO) phase distributed at grain boundaries along rolling direction. The sheet rolled at 300 °C was composed of deformed grains, substructures and excessive dislocations. With increasing final rolling temperatures from 300 °C to 400 °C, the volume fraction of recrystallized grains with relatively random orientations increased significantly. The strength of the rolled sheets was improved while the ductility was deteriorated with decreasing final rolling temperatures. The tensile yield strength and ultimate tensile strength of the sheet rolled at 300 °C reached 320 MPa and 416 MPa, respectively with the elongation to failure of 5.3%. The mechanical anisotropy of the rolling sheet became unity when rolled at higher temperature of 400 °C due to the formation of weaker basal texture.