Uniform fine microstructure and random texture of Mg-9.8Gd-2.7Y-0.4Zr magnesium alloy processed by repeated-upsetting deformation

摘要

Mg-Gd-Y is a new type of high performance magnesium alloy with high specific strength at both room and elevated temperature. A recently developed multiple compression severe deformation, repeated-upsetting (RU) processing is applied to further improve both strength and ductility. The microstructure and texture evolution of Mg-9.8Gd-2.7Y-0.4Zr Mg alloy large plate processed by RU are investigated, which are critical to provide a fundamental understanding of the improvement. Reasonably equiaxed spatially uniform micro-structure is obtained with a grain size of 2.5-3.0 μm. Randomized texture is achieved through 3D material flow by grain rotation due to imposed shear strain and Mg alloys specific tensile twinning. Reasonably stable {0002} basal texture along horizontal directions is related to tensile twinning mechanism.