Effect of Ca Addition on Mechanical Properties and the Ignition Temperature of Cast WE43 alloys

In this paper, WE43-xCa (0, 1, 2 wt%) magnesium alloys were prepared by electromagnetic stirring (EMS) casting, and the solid solution-treated WE43-xCa (1, 2 wt%) alloys were subjected to aging treatment at 225 °C for different times. The results showed that the grain size of the alloy is refined after the addition of Ca. However, when the Ca content was high, the continuous reticular phase distributed along the grain boundaries and the generated Mg 2 Ca brittle phase led to the degradation of the mechanical properties. After the 225 °C × 10 h aging treatment, the 1Ca alloy had the best mechanical properties with a tensile strength of 284 MPa, yield strength of 227 MPa, and elongation of 9.0%. This material could meet the requirements of structural parts of high-speed railways. The combustion temperature test exhibited that the WE43-xCa alloy was able to be kept at 900 °C without ignition. The addition of Ca resulted in the formation of thin and continuous CaO oxide film on the outermost layer of the alloy, which helped prevent internal oxidation of the alloy, thereby increasing the ignition temperature.