High Cycle Fatigue Properties and Fracture Behavior of Ti-5Al-5Mo-5V-1Cr-1Fe Titanium Alloy

Abstract

Under different stress concentration factors K_t and stress ratios R, the high cycle fatigue (HCF) properties and fracture morphologies of Ti-5Al-5Mo-5V-1Cr-1Fe (Ti-55511) forgings and bars in longitudinal orientation were studied at room temperature. The results show that both the fatigue strength of forgings and bars increases with the increasing stress ratio and decreases with the increasing stress concentration factor. The fatigue strength of forgings is 1.08∼1.57 times greater than that of bars. There are primary α phase particles in the forgings, with more uniform distribution and smaller size. However, there exist residual casting primary α phase particles with the shape of bulk or strip in bars.