Effect of Cr-Doping on the Structural and Magnetic Properties of Mechanically Alloyed FeCoNiAlMn_1–xCr_x High-Entropy Alloy Powder

Abstract

In this work, the new compositions of FeCoNiAlMn 1−x Cr x , (0.0 ≤ x ≤ 1.0), a high-entropy alloy powder (HEAP), are prepared by mechanical alloying (MA). The influence of Cr doping on the phase structure, microstructure, and magnetic properties is thoroughly investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry. It is found that this alloy has formed a simple body-centered cubic structure with a minute facecentered cubic structure for Mn to Cr replacement with heat treatment. The lattice parameter, average crystallite size, and grain size decrease by replacing Cr with Mn. The SEM analysis of FeCoNiAlMn showed no grain boundary formation, depicting a single-phase microstructure after MA, similar to XRD. The saturation magnetization first increases (68 emu/g) up to x = 0.6 and then decreases with complete substitution of Cr. Magnetic properties are related to crystallite size. FeCoNiAlMn 0.4 Cr 0.6 HEAP has shown optimum results with better saturation magnetization and coercivity as a soft magnet.