The effect of cooling rate on structure and corrosion resistance of Fe5CrCuNiMnSi and Fe5CоCuNiMnSi high-entropy alloys

Abstract

The structure, phase composition, electrochemical behavior, and corrosion resistance of high-entropy alloys Fe₅CrCuNiMnSi and Fe₅CоCuNiMnSi in as-cast and splat-quenched states were studied. A cooling rate estimated by splat-quenched film thickness was ~ 10⁶ K/s. Selecting the components of the studied alloys was carried out basing on the criteria adopted in the literature for the composition of a high-entropy alloy such as calculations of the entropy and enthalpy of mixing, valence electron concentrations as well as the difference between the atomic radii of the components. Using X-ray diffraction analysis, the phase composition and crystal lattice parameters of the investigated high-entropy alloys were determined. It was established that the as-cast Fe₅CоCuNiMnSi alloy is a solid solution with a face-centered cubic lattice, while the as-cast Fe₅CrCuNiMnSi alloy contains two solid solutions with a face-centered and solid solution with body-centered cubic lattices. However, both spalt-quenched high-entropy alloys were solid solutions with a face-centered cubic lattice. The values of stationary potentials and areas of electrochemical stability of alloys as well as the density of corrosion currents were determined. It was shown that samples of the Fe₅CrCuNiMnSi alloy behaved inertly in corrosion tests both in as-cast and in splat-quenched states.