Effect of texture and {10-12} twin on the low cycle fatigue properties of rolled AZ31 Mg alloy

The effect of texture and {10-12} twin on the low cycle fatigue properties of rolled AZ31 magnesium alloy was investigated by varying the loading direction and the amount of twin volume fraction, respectively. The hysteresis loops of the specimens loaded parallel to the rolling direction (RD) showed asymmetric nature in tension and compression, and were quite different from those of the specimens loaded normal to the rolling plane (ND). ND specimens showed superior fatigue properties than RD specimens due to the compressive mean stress. It was also found that the fatigue resistance could be modified by controlling its twinning- detwinning characteristics via a pre-straining process. Initial {10-12} twin generated by pre-compression along the RD improved fatigue resistance in proportion to the amount of pre-compression. Meanwhile, the pre-tension along the ND caused an increase of mean stress, and thus deteriorated the fatigue resistance of the material.