Enhanced strength and ductility by a core-shell-like distributed Laves phase in Cr15Ti25Zr25Hf25Sc10 high-entropy alloy

A Cr15Ti25Zr25Hf25Sc10 high-entropy alloy with superior strength and ductility was designed based on the Hashin-Shtrikman theorem. The alloy comprises dual-hexagonal closed-packed (HCP) phase cores embedded in much harder Laves phase shells, which improves the strength and ductility synchronously compared with a conventional structure with a finely dispersed strengthening phase. The formation and distribution of the Laves phases are controlled by Cr segregation to develop the core-shell structure. The interactions between dislocations, nanoprecipitates, dislocation tangles, and gradient laves-phase cell structures provide high compression plasticity and strength-ductility synergy. This work proves that the reverse thinking of adding hard phases to HCP structural materials can be used to obtain ideal material properties by adjusting the structural gradient.