Structure and magnetic properties of a multi-principal element Ni–Fe–Cr–Co–Zn–Mn alloy

•A hard magnetic, nanocrystalline NiFeCrCoMnZn alloy is produced.•The alloy forms a metastable solid solution after mechanical alloying.•After heat treatment, it precipitates multiple phases that impart its magnetic properties.•The phase formation was studied using diffraction, microscopy, and ab initio simulation.

A nanocrystalline alloy with a nominal composition of Ni20Fe20Cr20Co20Zn15Mn5 was produced by mechanical alloying and processed using annealing treatments between 450 and 600 °C for lengths from 0.5 to 4 h. Analysis was conducted using x-ray diffraction, transmission electron microscopy, magnetometry, and first-principles calculations. Despite designing the alloy using empirical high-entropy alloy guidelines, it was found to precipitate numerous phases after annealing. These precipitates included a magnetic phase, α-FeCo, which, after the optimal heat treatment conditions of 1 h at 500 °C, resulted in an alloy with reasonably good hard magnetic properties. The effect of annealing temperature and time on the microstructure and magnetic properties are discussed, as well as the likely mechanisms that cause the microstructure development.