“In the field of new materials, researchers have investigated the microstructure and mechanical properties of large differential pressure sand cast EV31A alloy castings, and found that the as cast microstructure of the alloy consists of small primary equiaxed α - Mg and eutectic Mg41 (Nd0.6Zn0.29Gd0.11) 5 phases, with an average α - Mg grain size of 65.02 μ m. After solid solution treatment, most of the Mg41 (Nd0.6Zn0.29Gd0.11) 5 phase dissolved into the matrix, with a very small amount remaining in the form of particles at the grain boundaries, and the average grain size increased to 74.33 μ m. The peak aging strengthening phase is β '+β 1, and the alloy has high comprehensive mechanical properties. At room temperature, the tensile strength is 312.3 MPa, the yield strength is 174.2 MPa, and the elongation is 6.9%. The tensile strength slowly decreases below 200 ℃, significantly decreases at 250 ℃, and the yield strength decreases linearly within the range of room temperature to 250 ℃, while the elongation rate increases linearly. The fracture mode at room temperature is cleavage fracture, quasi cleavage fracture at 100-200 ℃, and mixed fracture at 250 ℃.”