High-entropy alloy

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High-entropy alloys (HEAs) are alloys that are formed by mixing equal or relatively large proportions of (usually) five or more elements. Prior to the synthesis of these substances, typical metal alloys comprised one or two major components with smaller amounts of other elements. For example, additional elements can be added to iron to improve its properties, thereby creating an iron-based alloy, but typically in fairly low proportions, such as the proportions of carbon, manganese, and others in various steels. Hence, high-entropy alloys are a novel class of materials. The term "high-entropy alloys" was coined by Taiwanese scientist Jien-Wei Yeh because the entropy increase of mixing is substantially higher when there is a larger number of elements in the mix, and their proportions are more nearly equal. Some alternative names, such as multi-component alloys, compositionally complex alloys and multi-principal-element alloys are also suggested by other researchers. Compositionally complex alloys (CCAs) are an up-and-coming group of materials due to their unique mechanical properties. They have high strength and toughness, the ability to operate at higher temperatures than current alloys, and have superior ductility. Ductility quantifies the permanent deformation a material can withstand before failure, a key consideration in designing safe and reliable materials. Due to their enhanced properties, CCAs show promise in extreme environments. An extreme environment presents significant challenges for a material to perform to its intended use within designated safety limits. CCAs can be used in several applications such as aerospace propulsion systems, land-based gas turbines, heat exchangers, and the chemical process industry. These alloys are currently the focus of significant attention in materials science and engineering because they have potentially desirable properties. Furthermore, research indicates that some HEAs have considerably better strength-to-weight ratios, with a higher degree of fracture resistance, tensile strength, and corrosion and oxidation resistance than conventional...