A Kanni Raj

H E a A Kanni Raj

HEA: High-Entropy Alloys (also known as CCA or MPEA) - are equiatomic and nonequiatomic multicomponent alloys. The configurational entropy of these alloys is expected to be very high at their random solution states. Such a high entropy is expected to drive the tendency to form simple solid solutions (crystalline or amorphous) rather than complex microstructures with many compounds. These alloys do form simple solid solutions in most of the cases and the number of phases observed in these alloys is much less than the maximum predicted from the Gibbs phase rule. The researchers also feel that HEAs can substitute conventional materials in advanced applications so that the limitations of the latter in service life and operational conditions could be overcome by providing superior performance of the former. A number of processing routes, including conventional melting and casting, mechanical alloying, various coating techniques, and even combinatorial materials science approaches are being used to synthesize and process this new class of alloys. There have been a lot of studies on understanding both the structural and functional properties of these alloys. The results of HEAs and HEA-related materials reported so far by various research groups are very encouraging for their applications in a wide range of fields such as materials for engine, nuclear plant, chemical plant, marine structure, tool, mold, hard facing, and functional coatings. This book presents a comprehensive insight into all the above aspects of this exciting new class of alloys.