Lightweight porous high entropy alloy based on triple-phase eutectic structure matrix

Abstract

Porous metal materials often show great potential and practical application as structural materials and functional materials in energy, environment and other fields because of their unique structure and properties. This study utilized the potential difference between different phases to immerse the Co18Cr18Fe18Ni26Al10Nb10 triple-phase eutectic high entropy alloy (HEA) into aqua regia, selectively corroding the two phases, and preparing a porous material with a uniform structure. X-ray diffraction (XRD) and the energy dispersive spectroscope (EDS) indicate that the porous material is mainly composed of Laves phase, enriched with Nb element. Compression specimens were prepared into a composite material with porous material wrapping the parent alloy by dealloying method. When the immersion time is up to 3 h, the porous materials still lead to a promising property with a yield strength of 1553.45 MPa and specific strength of 232.55 KN·m/Kg with density of 6.7 g/cm3. This work provides a design strategy to obtain a HEA with lower density and higher specific strength by porous structure.