Comparative study on the fatigue properties and dislocation evolution of three kinds of aluminum alloys

The detecting and evaluating fatigue performance of aluminum alloys with wide applications have important engineering significance. Three types of aluminum alloys, 1060, 3003 and 6063, were selected to conducted research on tensile and high cycle fatigue properties. It can be found that the relationship between the tensile strength and fatigue strength is not monotonically increasing, the mechanism was also analyzed. The fracture surface and microstructure before and after fatigued were analyzed using scanning electron microscope and transmission electron microscope, the effect of "localized reinforcement" can make the fatigue strength of alloy higher, and the evolution of dislocations under cyclic loading have a significant impact on the tendency of mutisource cracking and fatigue performance. Meanwhile, the positions of knee points and the scatter of the fatigue SN curves were effect by the strength of materials.