Simultaneous enhancement of strength and hydrogen embrittlement resistance of laser-powder bed fusion maraging steel via long-term low-temperature aging

Abstract

This study reported an effective strategy for simultaneously enhancing the strength and hydrogen embrittlement resistance of laser-powder bed fusion(L-PBF) 18Ni300 maraging steel through a long-term low-temperature aging treatment (LTA). The beneficial roles of LTA are: (i) LTA produced a multi-scale and multi-dimensional hydrogen trap network composed of dispersed ω nanoprecipitates and dense cellular structures, which strongly hindered hydrogen enrichment at grain boundaries, thereby inhibiting hydrogen-enhanced decohesion. (ii) High-density ω precipitates not only enhanced the strength, but also affected H-dislocation interactions, thereby hindering hydrogen-enhanced localized plasticity. (iii) LTA eliminated the formation of austenite aggregation zone, reducing the additional risk of cracking.