Effect of annealing treatment on the fatigue behavior of titanium alloy self-piecing riveted joints

The stress relief annealing was applied to treat the whole titanium alloy self-piecing riveted joints, and the tensile and fatigue properties of the joints with and without heat treatment were tested. The F-lgN curves were obtained by fitting the data of the rivet joints fatigue test using three-parameter power function equation. The scanning electron microscope was applied to analyze the fracture of the fatigue samples, and the influence of stress relief annealing on fatigue property of the joints was investigated contrastively. The results showed that the stress relief annealing had a significant effect on the fatigue failure mode of the rivet joints that mainly fracture location of the rivet joint changed from the sheet to the rivet. The fatigue property of the joints could be improved by stress relief annealing in the middle life range but reduced in the long life range.