Advances in the Fundamental Understanding and Prospects for Practical Applications of High-entropy Materials

When the term “high-entropy alloys” was coined nearly twenty years ago, the claim that they represented a new paradigm in alloy design was met with skepticism. Within about ten years, however, the field exploded into a major topic in materials science. Now the high-entropy design strategy (i.e., using multiple elements in high concentrations instead of the conventional “base element” approach) is applied much more broadly than the initial focus of single-phase metallic solid solutions. Hence, the present Research Topic encompasses “high-entropy materials” and highlights research that stretches the original boundaries to include multi-phase systems, for example. Furthermore, the early skepticism and debate is far from resolved and this topic seeks to take a hard look at the so-called entropy hypothesis and better understand why some high-entropy materials show exceptional properties. Finally, we ask “where are the practical applications of high-entropy materials?” after nearly twenty years of research activity.

The role of entropy, particularly configurational entropy, in stabilizing and enhancing the properties of materials with multiple principal elements is still debated and needs to be better understood. Research that rigorously addresses the evolution of entropy in multi-element systems, including multi-phase systems, will address this need. Furthermore, research that identifies significant competing phenomena will help us understand why some high-entropy materials have shown exceptional properties such as high strength at elevated temperatures, while many others have not. Finally, high-entropy materials will not remain a hot research topic for long without practical applications and technological advances. The goal of this Research Topic is to highlight these applications, potential and actual.

Topics of interest include, but are not limited to:
• Practical applications of high-entropy materials
• Phase evolution in multi-principal-element systems
• Long and short-range ordering studies
• Engineering properties
• High-throughput experimental studies
• High-throughput computational studies
• Machine learning and artificial intelligence

The Editors and Frontier's Editorial Office would like to thank Dr. Chanho Lee for his advisory and supporting role in the proposal of this Research Topic.
Dr. Andreas Kulovits is currently employed at Arconic Technical Center as Staff Scientist. As he is an expert in High-entropy Materials, he will maintain objectivity and his current position should not pose any conflict for this project.