[High-Entropy Alloy, HEA]

#Multi-principal elements

#Sluggish diffusion#New alloy system

​

Most conventionally produced metallic materials, such as steel, titanium and aluminum alloys, are based on one, or rarely two, principal elements. To improve their mechanical and chemical properties, composition designs using various additional alloying elements have been studied. Unlike these conventional alloy systems, high-entropy alloy (HEA) systems contain at least five major elements, at concentrations ranging between 5 and 35 at%, and have attracted intensive research during the past decade[1–3]. The implicit hypothesis in the term“high-entropy” is that the entropic stabilization of a random solid solution phase is achieved against intermetallic com-pounds when numerous elements are mixed in an equimolar fraction[2,4]. This assumption is not always valid for all multi-component alloys because the high-entropy effect has overestimated the real mixing entropy of a HEA[3]. Nevertheless, the formation of a single solid solution phase of many HEAs has promising properties for various applications and has generated extensive research interest in the scientific community as well [4,5]. - from 'Materials Science and Engineering: A Volume 689, 24 March 2017, Pages 122-133'