Beyond the Limit of Specific Strength in Casting Metals via Dual Nanoprecipitates

Casting not only promotes the birth of early civilization but serves as the catalyst of the industrial revolution by raising productivity with bronze and iron. Although the achievement of strength-ductility synergy of casting alloy has been promoted by continual endeavor, it is still a challenge for casting alloys with superior specific strength beyond 200 MPa g –1 without the help of thermomechanical processing. Here, we screened a new composition and obtained a four-phase high-entropy alloy Ni 36 Fe 34 Cr 10 Al 17 Ti 2 Mo1 with a superior strength of 1630 MPa and elongation of 2.9% by a direct-cast approach. Surprisingly, the strength and ductility can be further increased to 1740 MPa and elongation to 8.7% via simple aging, with a historical specific strength of 242 MPa g –1 cm 3 . Improved strength arises from hierarchical microstructures with high-volume-fraction dual nanoprecipitates, and increased elongation arises from increased ductile FCC phase fraction and enhanced heterodeformation-induced stress.