Strong-yet-deformable interfaces to achieve mechanical robustness in CrCoNi-Al bimetal composites

Metal matrix composites reinforced with deformable metallic phases possess great potential for robust mechanical properties. However, realizing interfacial strain coordination remains a major challenge. Here, we developed CrCoNi-Al bimetal composite with strong-yet-deformable interfaces. The composite with ∼650 nm interfacial layer exhibited tensile strength of 327.1 ± 2.1 MPa and uniform elongation of 3.8 ± 0.2%, 12% and 58% greater than those of its untailored counterpart, while maintaining comparable total elongation (7.4 ± 0.5%). The favorable strength-ductility combination mainly originates from the strong-yet-deformable interface that facilitates the load-sharing of CrCoNi reinforcement, plastic co-deformation between constituent phases, and high energy dissipation through a ‘high-density, fine-microcrack’ damage-tolerance mode.