The role of cell structures in hydrogen embrittlement of L-PBF 18Ni(300) maraging steel

Abstract

This work analyzed the role of unique cell structures in hydrogen embrittlement of additively manufactured maraging steel. For comparison, some as built samples were solution treated to eliminate cell structures, producing the typical martensite where dislocations randomly distributed. By contrast, the cell structures constituted by dislocation tangles in as built samples introduced more hydrogen traps and delayed hydrogen diffusion, but caused much higher HE susceptibility, because the hydrogen accumulation around cell walls created locally hydrogen-enriched environment for the grain boundaries closely adjacent to cell walls, increasing the risk of intergranular cracking. Hydrogen susceptibility was markedly reduced after eliminating cell structures.