Hydrogen permeation behavior and hydrogen-induced defects in 316L stainless steels manufactured by additive manufacturing

Abstract

Additive manufacturing technology is a novel path to fabricate complex nuclear components. Considering the hydrogen (H) environment in which nuclear materials work, we proposed that the hydrogen resistance of structure materials should be considered as a deciding factor in the materials selection for nuclear application. In this work, we introduced H atoms into the selective laser melting (SLM) 316L stainless steel (SS) via two different H permeation methods and characterized its H permeation behavior and microstructure change. Results showed that the H diffusion rate in the SLM 316L SS was much higher than that in the cold-rolled (CR) one. The abundant sub-grain boundaries of the SLM 316L SS act as rapid transportation channels for the H atoms. H-induced defects which do not appear in the H charged CR 316L SS were observed in the H charged SLM 316L SS. H softening effect occurs in both SLM and CR 316L SS.