7.3 Interstitial Compounds (Hagg Phases).Intermetallics, Interstitial Compounds and Metallic Glasses in High-Entropy Alloys 6.5 Role of Sluggish Diffusion in Phase Evolution of HEAs.6.3 Solid Solution Formation in Nonequiatomic HEAs.6.2 Solid Solution Formation in Equiatomic HEAs.4.2 Integrated Computational Materials Engineering.Alloy Design in the Twenty-First Century: ICME and Materials Genome Strategies Among the high number of multi-principal-element alloys that are referred to as high-entropy alloys (HEAs) in the literature, only a limited number solidify. 3.5 Phase Separation Approach to Find Single-Phase HEAs.3.4 Pettifor Map Approach to Predict the Formation of Intermetallic Compound, Quasicrystal, and Glass.3.3 Parametric Approaches to Predict Crystalline Solid Solution and Metallic Glass.3.2 Mutual Solubility and Phase Formation Tendency in HEAs.3.1 Predicting Solid Solubility from Hume-Rothery Rules.2.2 Classification of Phase Diagrams and Alloy Systems.Thus, there has been signicant interest in these materials, leading to an emerging yet exciting new eld. Due to the distinct design concept, these alloys often exhibit unusual properties. A Brief History of Alloys and the Birth of High-Entropy Alloys High-entropy alloys (HEAs) are alloys with ve or more principal elements. Provides a comparison of HEAs with other multicomponent systems like intermetallics and bulk metallic glasses.Discusses the structural and functional properties of HEAs.Covers design of HEAs based on thermodynamic criteria.Encompasses the synthesis and phase formation of high entropy alloys.This book presents the fundamental knowledge present in the field, the spectrum of various alloy systems and their characteristics studied to date, current key focus areas, and the future scope of the field in terms of research and technological applications. Due to their unique properties, high entropy alloys have attracted considerable attention from both academics and technologists. These alloys are expected to have high configurational entropy and hence were termed as "high entropy alloys." HEAs have a broad range of structures and properties, and may find applications in structural, electrical, magnetic, high-temperature, wear-resistant, corrosion-resistant, and oxidation-resistant components. Yeh and his group first reported a new approach to alloy design, which involved mixing elements in equiatomic or near-equiatomic proportions, to form multi-component alloys with no single principal element. The conventional approach to alloy design is to select one principal element and add elements to it in minor quantities in order to improve the properties. Finally, future developments and potential new research directions for HEAs are proposed.This book provides a complete review of the current state of the art in the field of high entropy alloys (HEA). Modeling techniques applicable to HEAs are introduced and discussed, such as ab initio molecular dynamics simulations and CALPHAD modeling. Glass forming ability and plastic properties of high-entropy bulk metallic glasses are also discussed. The comparison between conventional and high-entropy bulk metallic glasses is analyzed from the viewpoints of eutectic composition, dense atomic packing, and entropy of mixing. We present a general route for alloying up to eight dissimilar elements into single-phase solid-solution nanoparticles, referred to as high-entropy-alloy nanoparticles (HEA-NPs), by thermally shocking precursor metal salt mixtures loaded onto carbon supports temperature 2000 kelvin (K), 55-millisecond duration, rate of 10 5 K per second. Great details are provided on the plastic deformation, fracture, and magnetization from the perspectives of crackling noise and Barkhausen noise measurements, and the analysis of serrations on stress–strain curves at specific strain rates or testing temperatures, as well as the serrations of the magnetization hysteresis loops. Physical, magnetic, chemical, and mechanical properties are then discussed. This paper first reviews HEA formation in relation to thermodynamics, kinetics, and processing. Furthermore, the general corrosion resistance of the Cu 0.5NiAlCoCrFeSi HEA is much better than that of the conventional 304-stainless steel. Up to date, many HEAs with promising properties have been reported, e.g., high wear-resistant HEAs, Co 1.5CrFeNi 1.5Ti and Al 0.2Co 1.5CrFeNi 1.5Ti alloys high-strength body-centered-cubic (BCC) AlCoCrFeNi HEAs at room temperature, and NbMoTaV HEA at elevated temperatures. The concept of high entropy introduces a new path of developing advanced materials with unique properties, which cannot be achieved by the conventional micro-alloying approach based on only one dominant element. HEAs are loosely defined as solid solution alloys that contain more than five principal elements in equal or near equal atomic percent (at.%). This paper reviews the recent research and development of high-entropy alloys (HEAs).