The super-long fatigue behavior of the as-extruded ZK60 magnesium alloy
挤压态镁合金ZK60的超高周疲劳行为

In the super-long fatigue life regime (106~109 cyc), the fatigue behavior of the as-extruded ZK60 Mg alloy was studied. The results revealed that a plateau existed in the regime of 5×106 ~ 108 cyc, whereas the fatigue strength gradually decreased in the regime of 108~109 cyc, and the fatigue strength corresponding to 109 cyc was 90±5MPa. SEM fracture observation indicated that the fatigue crack mostly initiated at the surface or subsurface for the samples failed in the regime of 5×106 ~108 cyc, and at the interior non-metallic inclusion for the samples failed between 108 and 109 cycles. According to the observation and determination of the region size of the crack initiation, the fatigue strength was estimated, and compared with the experimental result.