Grain refinement and reduced yield asymmetry of extruded Mg-5Sn-1Zn alloy by Al addition

We report that the addition of 1-4.5 wt% Al to Mg-5Sn-1Zn alloy results in grain refinement and a significant decrease in yield asymmetry in the extruded condition. The Mg-5Sn-1Zn alloy with 4.5 wt% Al showed nearly symmetric yielding behavior at room temperature, exhibiting a compressive-to-tensile yield strength ratio of 0.99. The reduced yield asymmetry is discussed in terms of microstructure and texture.