Effect of morphology of long period stacking ordered phase on mechanical properties of Mg-10Gd-1Zn-0.5Zr magnesium alloy

The effect of morphology of long period stacking ordered (LPSO) phases on the mechanical properties of Mg-10Gd-1Zn-0.5Zr (wt%) alloy is investigated in this study. Three solution treatment processes are carried out on the alloy for obtained various morphologies of LPSO phases. The block LPSO phases, lamellar LPSO phases and no LPSO phase are observed after the solution treatments. The mechanical properties of the alloys in solution-treated and peak-aged conditions are tested. In the solution-treated condition, the block LPSO phases along grain boundaries have little influence on the mechanical properties, while the lamellar LPSO phases within the matrix decrease the ductility. In the peak-aged condition, the alloy with block LPSO phases shows the best tensile properties: ultimate tensile strength of 303.5 MPa and elongation of 7.7%. The results indicate that the interaction between LPSO phase and predominant strengthening β′ phase has a great influence on the mechanical properties of the alloy.