Effects of Gd concentration on microstructure, texture and tensile properties of Mg-Zn-Gd alloys subjected to large strain hot rolling

The Mg-2.0Zn-(0.1, 0.3)Gd (wt%) alloy sheets were fabricated by single pass large strain hot rolling at 300 °C with 80% reduction and their microstructure, texture and tensile properties were investigated. A fully recrystallized microstructure and weak basal texture were observed in the rolled Mg-2.0Zn-0.1Gd sheet while a heterogeneous, deformed microstructure consisting of many shear bands and numerous intersected twins was found in the rolled Mg-2.0Zn-0.3Gd sheet. The RD-tilting double-peaks texture component was observed in both alloys and indicated that the pyramidal 〈c+a〉 slip was activated during the rolling process. Texture evolution revealed that the texture weakening effect owing to the growth advantages of the non-basal orientated grains which nucleated at shear bands. Room temperature tensile testing demonstrated that the annealed Mg-2.0Zn-0.3Gd sheet showed a high elongation to failure of 35% while the annealed Mg-2.0Zn-0.1Gd sheet showed a low ductility of about 20% which were due to different textures.