Very High‐Cycle Bending Fatigue Properties of Selective Laser Melted TC4 Alloys

Titanium alloys manufactured using selective laser melting (SLM) technology have found widespread applications in aerospace and other industries. However, there is a significant lack of high‐cycle fatigue S–N curves for titanium alloys manufactured by SLM, particularly for fatigue data in the range of 10⁷–10⁸ cycles. This lack of data limits the ability to assess fatigue life under wide‐frequency vibration conditions. Herein, very high‐cycle fatigue (VHCF) tests are conducted on TC4 titanium alloys manufactured by SLM in both vertical and horizontal orientations, and the corresponding S–N curves are obtained, which address the critical gap in VHCF data for SLM‐manufactured TC4 titanium alloys under bending fatigue conditions, particularly in the range of 10⁷–10⁸ cycles. Subsequently, the fracture surfaces are examined and analyzed using an optical microscopy and a scanning electron microscopy, and defect dimensions are measured by computed tomography scan system. Finally, the fatigue performance of the SLM‐manufactured titanium alloys is compared with that of the conventionally manufactured titanium alloys.