Influence of solution temperature on fatigue behavior of AM-SC1 cast magnesium alloy

The microstructure, tensile properties and high cycle rotary bending fatigue behavior of low pressure sand cast (LPSC) AM-SC1 Mg alloy, solution-treated at 525, 540 and 560 °C respectively and then aged at 215 °C, were studied. The solution temperature has little influence on the average grain size of LPSC AM-SC1 alloy, but decreases the size and content of the residual secondary compounds when solution temperature increases. Compared with the alloy solution treated at 525 and 540 °C, the alloy treated at 560 °C shows obviously higher yield strength (+19 MPa) and ultimate tensile strength (+24 MPa), comparable elongation, and higher rotary bending fatigue strength (+8 MPa). However, when the fatigue stress amplitude is higher than the fatigue strength, the 560 °C solution treated alloy shows an obvious lower fatigue life. The fatigue fracture behavior of LPSC AM-SC1 alloy was discussed as well in this paper.