Fatigue crack propagation behavior of an as-extruded magnesium alloy AZ80

An investigation of the fatigue crack propagation (FCP) behavior of the as-extruded magnesium alloy AZ80 was made by means of the constant load amplitude fatigue test, scanning electron microscope (SEM), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES). The results demonstrated that loading frequency had a significant influence on fatigue crack propagation rate, and it increased with a decrease in loading frequency and an increase in load ratio. Crack closure induced by plasticity rather than oxide film might play a predominant role in fatigue crack propagation. The coalescence of the microvoids was proposed to be the mechanism of fatigue crack propagation of the extruded magnesium alloy AZ80.