Microstructure and defect sensitivities in the very high-cycle fatigue response of Laser Powder Bed Fused Ti–6Al–4V

This work aims to analyze the sensitivity of the very high-cycle fatigue behavior of LPBF-Ti-6Al-4V to microstructure and porosity variations. To do so ultrasonic fatigue testing is performed on five grades of LPBF-Ti-6Al-4V. These grades were generated using different LPBF process parameters and different thermal post-treatments allowing to separately investigate the sensitivity to microstructure and porosity variations. It was found that both material features highly influenced the VHCF properties of LPBF-Ti-6Al-4V revealing the sensitivity to these features. Furthermore, the largest defect (pore or grain) controls fatigue crack initiation. [Display omitted] •Generation of Laser Powder Bed Fused specimens with reproducible target porosities.•Developed methodology to separately study microstructure and porosity effects.•VHCF testing was sensitive to both porosity and microstructure variations.•The largest defect (pore or grain) controls fatigue crack initiation.