Cryogenic-Mechanical Properties and Applications of Multiple-Basis-Element Alloys

Multiple-basis-element (MBE) alloy was defined as the entropy of mixing over 1R (R is the gas constant, 8.31 J/k), and contains at least three principal elements, each one at over 5%. Thus, MBE alloys can include high-entropy alloys (HEAs), medium-entropy alloys (MEAs), amorphous alloys, and some martensite stainless steels, which have been reported to possess excellent cryogenic properties. This paper reviews the progress of the cryogenic-mechanical properties and applications of MBE alloys. It has been concluded that, with the increase of entropy, the ductile-brittle-transition temperatures (DBTT) can be decreased to the liquid helium temperature (4.2 K). In summary, the cryogenic toughness of MBE alloys can be greatly enhanced by entropy adjustments, which is beneficial to their application at low temperatures.