Influence of hydrogen on the stress-relaxation properties of 17-4PH martensitic stainless steel manufactured by laser powder bed fusion

Abstract To evaluate the interactions between hydrogen and the mechanical behavior of additively manufactured (AM) 17-4PH martensitic stainless steel (MSS), stress-relaxation tests were performed for both non-charged and hydrogen-charged samples. Similar tests were performed for the conventional 17-4PH MSS counterpart (CM). The results clearly indicated significant differences in the relaxation properties between the CM and AM MSSs in the H900 state, which were attributed to the higher reversed austenite amount in the AM MSS than that in the CM MSS. In particular, the influence of hydrogen on the dislocation mobility in the austenite was clearly shown.