| Abstract Scope |
Martensitic steel is known to be vulnerable to hydrogen embrittlement (HE). The introduction of chemically heterogeneous microstructures into martensitic steels has improved tensile properties, thanks to chemically stable retained austenite. However, retained austenite is known to have both beneficial and detrimental effects on HE resistance. In this study, the influence of chemically heterogeneous microstructures on HE resistance in martensitic steel was investigated. Despite its excellent stability, retained austenite underwent strain-induced martensitic transformation under highly stressed conditions. However, under low-stress conditions, it remained as retained austenite and acted as a hydrogen trap site, enhancing HE resistance. These tendencies were more clearly observed in constant load tests, rather than slow strain rate tensile tests. Therefore, depending on the hydrogen environment, introducing retained austenite through chemical heterogeneity in martensitic steel could be an effective method for improving HE resistance. |