Effect of deformation speed on microstructure evolution and mechanical property of Mg-Gd alloys

The effect of deformation speed on microstructure and mechanical property was investigated in Mg1Gd and Mg3Gd alloys, and annealing of high-speed deformed samples was studied. Twinning was a dominant deformation mechanism after low-speed and high-speed compressions, while twin variant and type diversities were observed. Low-speed and high-speed deformed samples showed difference in twin amounts instead of twin types. Low-speed deformed samples exhibited more {10 (1) over bar2} tension twins (including unusual tension twins), while amount of {10 (1) over bar2} - {10 (1) over bar2} twin boundaries soared in high-speed deformed samples that contained less tension twins. {10 (1) over bar1} contraction twins and {10 (1) over bar1} - {10 (1) over bar2} double twins were relatively less activated after both low-speed and high-speed deformations. During annealing, hardness fluctuated because of competition between twin boundary segregation and recovery, while a higher alloying content would lead to a higher hardening rate as well as an extended hardening stage.