Cryogenic-enhanced HDI hardening in a heterostructured Cu-Sn alloy for strength-ductility-conductivity synergy

Achieving a superior balance of strength, ductility, and electrical conductivity remains challenging in Cu alloys because conventional strengthening strategies usually sacrifice one or more of these properties. Here, a heterostructured Cu-Sn alloy was fabricated by dynamic offsets and shear force adjustment cryorolling followed by annealing. The alloy consists of recrystallized coarse-grained soft domains and lamellar non-recrystallized hard domains, enabling effective strain partitioning during deformation. At 293 K, it exhibits an ultimate tensile strength of 401 MPa, a uniform elongation of 11.1%, and an electrical conductivity of 87.6% IACS. At 77 K, both strength and ductility increase simultaneously to 510 MPa and 28.1%, respectively. These results indicate that cryogenic-enhanced HDI hardening plays a key role in the superior mechanical response and highlight heterostructure design as an effective strategy for developing high-performance Cu alloys with balanced structural and functional properties.