Beyond strength-ductility trade-off: 3D interconnected heterostructured composites by liquid metal dealloying

Abstract

A breakthrough in the strength and ductility trade-off is crucial for the development of advanced metallic materials. Herein, we present a novel heterostructured composite composed of immiscible magnesium (Mg) and ferrochrome (FeCr) with a 3D interconnected morphology and synthesized by liquid metal dealloying. Soft Mg and hard FeCr zones mutually interlock with each other. This unique interpenetrating-phase configuration leads to a significant alternation of their intrinsic mechanical properties, especially in the soft Mg zone. It causes a strong forest hardening effect, resulting in a high initial dislocation density, and the surrounding hard zones create hydrostatic pressure at the soft zone under tension. The measured yield strength of the composite is close to the upper rule of mixture while its tensile elongation is larger than that of the mixture. These outstanding mechanical properties originate from the synergetic interaction between the soft and hard zones through the immiscible interface zone. The current 3D interconnected heterogeneous composite acts a guideline for the design of advanced materials possessing physical properties beyond expectations. © 2021