Notch fatigue and crack growth resistance of Ti-6Al-4V ELI additively manufactured via selective laser melting: A critical distance approach to defect sensitivity

This work is aimed at exploring the applicability of the theory of critical distances to the notch fatigue prognosis of Ti-6Al-4V ELI additively manufactured via selective laser melting. Particular attention is paid on investigating how the defectiveness influences the material critical length and the path followed by the fatigue cracks after nucleation. Fully-reversed axial fatigue tests are carried out on notched specimens of different severity and macrocrack growth tests are performed to determine the crack growth threshold ΔKth. The critical distance lengths are estimated according to a critical distance inverse search procedure and compared with the value deduced from ΔKth.