Notch fatigue behavior of a titanium alloy in the VHCF regime based on a vibration fatigue test

The notch fatigue behavior of a titanium alloy TC17 in the very high cycle fatigue (VHCF) regime is investigated by a vibration-based bending fatigue test. A complete S -N relation of notched specimens with high resonance frequencies is obtained, covering the lifetime up to 109 cycles, and the fracture surfaces are observed. The results show the TC17 exhibits relatively high fatigue notch sensitivity. Several fatigue crack initiation mechanisms relevant to the notch are then revealed. Furthermore, a notch fatigue prediction model based on a modified theory of critical distance is proposed by introducing a special weight function, which is demonstrated to have good prediction accuracy.