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

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 microstructure 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.

► A novel severe deformation technique, repeated-upsetting (RU) was reported. ► Mg–9.8Gd–2.7Y–0.4Zr (wt.%) alloy does not show the yield asymmetry after RU. ► A homogeneous microstructure is reached with a mean grain size of ~ 2.8 μm. ► Randomized texture is achieved through 3D material flow during RU.