Fatigue response of various titanium alloys to shot peening

The fatigue response of the various titanium alloy classes (alpha, alpha+beta and beta) to shot peening is evaluated. Results on the alpha-alloy Ti-2.5Cu show marked lifetime improvements compared to the electropolished reference. In contrast, the fatigue life improvements for the beta-alloys Ti-10V-2Fe-3Al and Ti-3Al-8V-6Cr-4Mo-4Zr are rather small. Intermediate life improvements were observed on the (alpha+beta)-alloy Ti-6Al-7Nb, Subsurface fatigue crack nucleation sites were observed on the alpha- and (alpha+beta)-alloys while cracks nucleated at the surface on the beta-alloys. The different response of the various alloy classes is explained by differences in cyclic deformation behavior. The results on cyclic hardening/softening correlate with the observed crack nucleation sites.