4 - Characterization and properties of high-entropy alloys materials

Abstract

High-entropy alloys (HEAs) are a relatively new class of materials that have been attracting significant attention in material science and engineering research. This chapter provides an introductory discourse on the microstructural characterization and properties of these fascinating materials. The term “HEAs” refers to an innovative concept of metallic materials composed of multiple principal elements, each with concentrations between 5% and 35%. Unlike conventional alloys, which typically comprise one principal element with minor alloying additions, HEAs possess a unique composition that can lead to a singularly rich and complex microstructure. This unique microstructure, in turn, imparts HEAs with extraordinary mechanical, thermal, and chemical properties, making them favorable candidates for high-performance applications across various industries. This chapter aims to elucidate the intricate connection between the microstructure and properties of HEAs. We will delve into the various characterization techniques used to study the microstructures of these alloys, such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD), among others. Fundamental aspects, such as phase formation, crystal structure, grain boundaries, and dislocation behavior, will be explored, shedding light on the mechanisms that engender the remarkable properties of these materials.