Investigation on the Very High Cycle Fatigue Life of Titanium Alloys by Near-β Forging and Shot Peening

In order to enhance the fatigue properties of metallic materials, a feasible rationale is to delay or prevent the interior and surface fatigue crack initiation. Based on this rationale, the study investigates the approach of improving the very high cycle fatigue properties of TC6 titanium alloys through near-β forging coupled with shot peening, conducted at 930 ℃ and ambient temperature, respectively. To unveil the associated mechanisms, microstructure, microhardness, residual stress, and fatigue properties are thoroughly analyzed after each process. Results indicate a considerable refinement in microstructure and significant mitigation of the initially existed strong texture post near-β forging and annealing, efficiently delaying crack initiation and propagation. As a result, the very high cycle fatigue property of TC6 achieves remarkable enhancement after forging. Compared to near-β forging, shot peening might not necessarily improve the very high cycle fatigue performance, particularly beyond 10⁶ cycles.