Hierarchical strategy toward strong and ductile austenitic stainless steel for cryogenic application

In cryogenic applications related to energy, lightweight design and transportation, there is a pressing need for strong and ductile structural alloys. An intriguing challenge lies in developing a strategy to enhance both properties under harsh environments. In this study, through the architectural of a hierarchical microstructure, we have successfully developed an austenitic stainless steel with an ultimate tensile strength exceeding 1.8 GPa and a uniform elongation of more than 40 % at cryogenic temperatures . This hierarchical stainless steel exhibits a remarkable improvement in both strength and strain hardening capacity compared to homogeneous counterparts. This enhancement can be attributed to the hetero-deformation induced effect coupling with progressive and sufficient martensite transformation , enables the maximal utilization of phase transformation-induced plasticity. Our findings offer a practical approach for boosting the strength and ductility of commercial materials in cryogenic conditions.