Multiscale Microstructure Architecturing Protects Advanced High Strength Steel against Hydrogen Embrittlement

Advanced high-strength steels exhibit structural and chemical ordering and patterning phenomena across multiple length scales. These include short and medium-range chemical ordering, complex nanoprecipitate patterns, and coupled mesoscopic chemical-structural-mechanical partitioning effects. These phenomena can arise from kinetic freezing, chemical decoration of lattice defects, locally confined phase transformation effects, or chemical container phases that trigger local phase transformations.<br/>Heat treatment can be used to architect these features in a hierarchical manner at bulk scale in medium and high manganese steels with lean chemical compositions [1,2]. These hierarchical ordering effects that involve different chemical and structural features across several length scales can be used to design a complex strain hardening behaviour and can help to enhance the materials' resistance to hydrogen embrittlement.<br/><br/><br/>1. Sun, B. et al. Chemical heterogeneity enhances hydrogen resistance in high-strength steels. Nat. Mater. 20, 1629–1634 (2021).<br/>2. Raabe, D. et al. Current Challenges and Opportunities in Microstructure-Related Properties of Advanced High-Strength Steels. Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 51, 5517–5586 (2020).