Research on model of fatigue microcrack-nucleating in aluminum alloy

The fatigue tests for LY12 aluminum alloys specimens under various stress levels were performed. The categories of the microcracks nucleating were determined using scanning electron microscopy (SEM) measured from specimens surfaces. The experiment results show a large number of micro cracks could incubate from cracked particles under a higher stress ratio, and incubate from deboned particles under a higher maximal stress. The microcracks formation models of fractured particles and deboned particles were presented.