Evaluation of Microstructure and Phase Formation in Nanocrystalline FeCoCuNbMo High-Entropy Alloy Synthesised by Mechanical Alloying

Abstract

High entropy alloys (HEAs) have gained significant consideration in materials science and engineering due to their stable phases. These alloys are made up of five or more major elements in equimolar or near-equimolar proportions, enabling them to harness the properties of multiple elements rather than depending on a single one. In this study, nanocrystalline FeCoCuNbMo high-entropy alloy powders were synthesised via the mechanical alloying method with high energy SPEX ball milling. The microstructures and crystal properties of the milled powders at regular intervals of milling were investigated through X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). XRD analysis revealed the BCC phase formation after 20 hours of milling. A study of diffraction patterns was conducted to find out average crystallite size and internal strains utilizing Scherrer’s formula and Williamson–Hall analysis, based on a uniform deformation model. Additionally, changes in particle size as a function of milling time were studied using nano zeta potential analysis. As milling time increased, the crystallite sizes decreased due to dislocations and stacking faults in crystals, and nano-crystalline structure formations were observed after 20 h of milling.