Long fatigue crack propagation behavior of laser powder bed-fused inconel 625 with intentionally-seeded porosity

Inconel 625 coupons were manufactured via laser powder bed fusion with different levels of intentionally-seeded porosity (up to 2.7%). The processing-induced porosities, morphologies and distributions were measured via Archimedes method and computed tomography. Tensile tests were performed, followed by fatigue crack propagation characterization. The static strength characteristics were not strongly affected by the levels of porosity, but the elongation at break was severely impacted. In the near threshold region of the Paris diagram, porous specimens were unaffected by porosity and build orientation. However, under higher stress intensity factors, the effect of porosity was found to be significant and build orientation-dependent.