Engineering prediction of fatigue strength for AM50 magnesium alloys

In the automotive industry, the use of magnesium alloys is increasing due to their low weight and relative good mechanical properties. However, the variable loading conditions require knowing the fatigue properties of these alloys. The paper presents original results for fatigue strength of AM50 magnesium alloy used for die casting of steering wheels. Three different types of specimens were tested in rotating bending in order to determine the fatigue strength of AM50 magnesium alloy. The effects of stress concentration and surface finishing are also investigated. The fatigue strength at 106 cycles was obtained 55.85 MPa for un-notched finished specimen and decrease for as casted R-radius specimens with 25%, respectively with 61.2% for V-notch specimens. Finally, correlations of fatigue strength with tensile strength and HV hardness are proposed, which are helpful in the design stage of magnesium alloy components.