Exceptional strength–ductility combination of heterostructured stainless steel for cryogenic applications

Heterostructured materials have been demonstrated as a new route to improve the strength–ductility trade-off of metallic materials. However, their mechanical performance at cryogenic temperatures has been scarcely explored. This study investigates the mechanical properties and phase transformation of a heterostructured and antimicrobial stainless steel (HS&AMSS), 316L+Cu, at a cryogenic temperature of 77 K. By using in-situ neutron diffraction, we revealed real-time phase evolution under tensile deformation. The HS&AMSS demonstrated exceptional mechanical properties at 77 K, including a significantly higher yield strength of 1400 MPa combined with an excellent ductility of 36 % compared to conventional stainless steels and heterostructured multicomponent alloys. The outstanding mechanical performance is attributed to the synergistic effect of multiple strengthening and strain hardening mechanisms. These findings suggest that HS&AMSS is a promising material for applications requiring robust mechanical properties in cryogenic environments, such as hydrogen storage, aerospace, superconducting magnets and polar infrastructure.