High-Entropy Alloys

High Entropy Alloys (HEAs), or Multi-Principal Element Alloys (MPEAs) are an intriguing class of metallic materials, based on a novel approach to materials design. Contrary to conventional alloying, these materials do not have a principal component, but are instead based on near equiatomic mixtures of five or more elements. Traditional metallurgical wisdom would expect the microstructure of these materials to contain a number of intermetallic phases, yet surprisingly, this has not to been the case. Experimental studies have reported single or dual phase as-cast microstructures, and corresponding diffraction data have indicated that these phases have simple crystal structures, such as fcc or bcc.