The creep and fracture behavior of additively manufactured Inconel 625 and 718

Additive manufacturing of alloys has gained attention by industry as it provides economical production of complex-configuration engine parts with fewer joining steps and greater geometric freedom. The creep behaviour of additively manufactured (AM) Inconel 625 and 718 at 650 and 800 degrees C was compared with that of the wrought alloy after 24 hour and long-term tests up to about one year. Inconel 718 is precipitation strengthened while 625 is solid-solution strengthened. It was discovered that the creep strength of the 625 and 718 produced by additively manufacturing is essentially identical than that of the wrought alloy. Complications occur, however, with a marked loss of ductility in the AM alloys. Fatigue and impact toughness were adversely affected as well. The basis for these degradations was particularly investigated.