Effect of Sm on twinning behavior of Mg-Gd-Y-Zr alloy at room temperature compression

Twining plays an important role in adjusting the mechanical properties and microstructure in magnesium alloys at room temperature deformation. In this work, the Mg-6Gd-3Y(-3Sm)-0.5Zr alloy was compressed at room temperature to study the effect of the Sm element on the twinning behavior. The results showed that twin of Mg-6Gd-3Y(-3Sm)-0.5Zr alloy after compressive deformation was {10-12} twin. In Mg-6Gd-3Y-0.5Zr alloy, there was coarse parallel twin, while in the Mg-6Gd-3Y-3Sm-0.5Zr alloy, there was a lot of fine cross twin. The variation of activated twin in Mg-6Gd-3Y-3Sm-0.5Zr alloy does not obey Schmid law. The activated cross twin variation in Mg-Gd-Y-Sm-Zr alloy can be divided into single-variant cross twin and multi-variant cross twin, both of which lead to changes in orientation differences. The large number of fine cross twin lead to matrix divided. This strengthened fine grains and the Mg-Gd-Y-Sm-Zr alloy showed high deformation stresses.