Centrifugal Metallothermic SHS of Cast Co-Cr-Fe-Ni-Mn-(X) Alloys

A relatively new approach to obtaining metal materials containing several principal elements in equiatomic concentrations which look promising for replacing commercially used alloys is proposed. Such materials are called high-entropy alloys (HEAs). Studies show that HEAs tend to form a simple solid-solution structure and can also contain ordered intermetallic phases. Such a method of forming metal materials can be regarded as a background for producing new HEAs with elevated performance characteristics. Most studies focus on the relationship between microstructure and measured properties; significantly less attention is paid to studying and developing new effective methods for creating HEAs. In this paper, we study the possibility of obtaining CoCrFeNiMn-(X) HEAs by centrifugal metallothermic SHS. Chemical and technological modes of modifying cast CoCrFeNiMn alloy during synthesis (in situ) by introducing alloying components into the starting exothermic compositions are tested for the first time. The microstructure and phase composition of NiCrCoFeMn alloys synthesized from mixtures containing Ti-Si-B(C) or Al are characterized. The microstructure of CoCrFeNiMn-(Ti-Si-B(C)) HEAs is found to consist of an HEA-based matrix and new structural inclusions of carbides and borides of titanium. High-Al CoCrFeNiMn-Al HEAs are represented by a composite structure containing NiAl as a basis and dispersion nanoprecipitates (similar to 100 nm) of a Cr- and Fe-based solid solution.