Effect of aging temperature on mechanical and fatigue properties of Ti-5Al-5V-5Mo-1Cr-1Fe alloy processed by radial-shear rolling

In this study, the effect of aging temperature on the mechanical and fatigue properties of the Ti-5Al-5V-5Mo-1Cr-1Fe alloy treated by radial-shear rolling was investigated. Increasing the aging temperature from 450 up to 520 °C gave rise to coarsening of the microstructure and enhancing of the volume fraction of the a-phase from 58 to 71 %. As a result, the ultimate tensile strength decreased slightly, but both ductility and fatigue performance at a cycling frequency of 5 Hz increased. In the high-cycle fatigue regime, the regularities of the initiation and propagation of cracks, as well as the evolution patterns and ultimate sizes of the fracture surface zones were revealed. In addition, both critical level of stress intensity factors and general relationships between the crack propagation and the fatigue performance were assessed. The obtained results suggested that used combinations of radial-shear rolling and subsequent aging is a promising treatment for critical components made of the Ti-5Al-5V-5Mo-1Cr-1Fe alloy operated under low-frequency high-amplitude loads.