Comparative investigation of small punch creep resistance of Inconel 718 fabricated by selective laser melting

Creep performance of selective laser melting (SLM) fabricated Inconel 718 is studied in comparison with that of as-forged and as-cast Inconel 718 via small punch creep test technique. The results show that the SLM-fabricated samples have a time to rupture approximately equal to that of the as-forged samples but much less than the as-cast sample due to the difference in the microstructures introduced by these manufacture processes. Intergranular fracture occurred in all the samples. For the SLM-fabricated Inconel 718, cracks initiated from the brittle Laves phases at grain boundaries during the creep process and may speed up the creep and lead to the failure of the sample. “Track-track” melt pool boundaries as one of the important interfaces in SLM-fabricated material can lead to a change in the cracking direction.