Tension-compression asymmetry in hot-rolled Mg-3wt%Gd alloy under creep loading

Creep stress including tensile loading and compressive loading was carried out on hot-rolled Mg-3wt%Gd alloy at 473 K along the rolling direction (RD) and the normal direction (ND) separately. For briefness, T-RD was applied to representing the sample under tensile creep loading along the RD. The other three samples were named C-RD, T-ND and C-ND, respectively. The results of creep tests showed an obvious tension-compression asymmetry along both the RD and the ND. Twinning deteriorated the creep resistance of the C-RD and the T-ND samples, and caused the resultant asymmetrical behavior. The T-RD sample had the best creep resistance, followed by the CND sample, and the last two samples with similarly poor creep resistance were the C-RD and the T-ND. During creep loading, the T-RD sample was controlled by cross-slip containing a-dislocations. The C-ND sample were dominated by basal slip and pyramidal c+a c+a c+a slip, inhibiting twinning and impairing basal slip.

Automated summary

The results of the study demonstrated a clear tension-compression asymmetry in the creep behavior of the alloy under tensile and compressive creep loading along the rolling direction and the normal direction. Twinning played a role in deteriorating the creep resistance of certain samples and causing asymmetrical behavior in the results. The T-RD sample showed the best creep resistance, while the C-ND sample followed, with the C-RD and T-ND samples showing similarly poor creep resistance.