A composition design of Mg rare earth alloys based on the total solute control was carried out. By screening the elements to inhibit the eutectic phase content in magnesium alloys

the effects of alloy composition on the non-equilibrium solidification structure

solidification interval

fluidity and crack resistance of the cast magnesium alloy were investigated

and the heat treatment process was optimized. The results reveal that the large and complex structural parts prepared with Mg-5.8 Gd-3.0 Y-0.4 Zr under the slow cooling conditions of sand mold present excellent mechanical properties

where mechanical properties reach more than 300 MPa in tensile strength

more than 220 MPa in yield strength

and more than 3% in elongation

meeting the requirements for comprehensive strength and toughness of large and complex structures with heavy loads and overloads.