The Effects of Anodization Treatment on the Microstructure and Fatigue Behavior of 7075-T73 Aluminum Alloy

The fatigue behaviors of 7075-T73 alloy with/without anodization/sealing treatment were investigated in this study. The microstructure of different samples was analyzed by electron microscopy. As the experiments, the microstructure were observed from the anodized/sealed samples to indicate that precipitates trapped at subsurface near film/metal (f/m) interface would partly dissolved and the deformed matrix existed high fractions of high angle grain boundaries. The bare 7075-T73 alloy samples achieved fatigue strength of 225 MPa and the anodized/sealed samples enhanced their fatigue strength at 107 life cycles with 10-20 mu m film thickness. The fractured anodized/sealed sample showed fine striation spacing than bare sample after subjected to low stress amplitude.