Influence of Surface Skin on the Fatigue Properties of Die-Cast Magnesium Alloy AS21X
The influence of the surface condition and elevated temperature on the fatigue properties of high pressure die cast magnesium alloy AS21X was investigated. Separately cast specimens were tested under tensile cyclic loading, at room temperature and 150°C. With the as-cast surface layer intact, no significant temperature influence on fatigue life was found for large stress amplitudes, whereas the fatigue strength at 107 cycles was found to drop from 50 MPa at 20°C to 40 MPa at 150°C. Fracture surface analysis revealed that the predominant fatigue cracks originated from pre-existing surface defects.
T.T. Lamark et al., "Influence of Surface Skin on the Fatigue Properties of Die-Cast Magnesium Alloy AS21X", Materials Science Forum, Vol. 482, pp. 379-382, 2005