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

摘要

The Mg-2.0Zn-(0.1, 0.3)Gd (wt%) alloy sheets were fabricated by single pass large strain hot rolling at 300 ℃ 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-0.1 Gd 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 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.