Hollow medium-entropy alloy nanolattices with ultrahigh energy absorption and resilience

Hollow micro/nanolattices have emerged in recent years as a premium solution compared to conventional foams or aerogels for mechanically robust lightweight structures. However, existing hollow metallic micro/nanolattices often cannot exhibit high toughness due to the intrinsic brittleness from localized strut fractures, limiting their broad applications. Here, we report the development of hollow CoCrNi medium-entropy alloy (MEA) nanolattices, which exhibit high specific energy absorption (up to 25 J g−1) and resilience (over 90% recoverability) by leveraging size-induced ductility and rationally engineered MEA microstructural defects. This strategy provides a pathway for the development of ultralight, damage-resistant metallic metamaterials for a myriad of structural and functional applications. This work demonstrates medium-entropy alloy (MEA) hollow nanolattices with high toughness and resilience, by leveraging size-induced ductility and rationally engineered MEA microstructural defects, suggesting a new pathway for lightweight mechanical metamaterials with simultaneous high strength, toughness, and recoverability for engineering applications.