The effect of some late 3d transition metals additions to a Fe–Mn–Al–C alloy on the development of high-entropy alloys

Abstract

In this study, we introduce a new series of Fe–Mn–Co–Ni–Cu–Al–C alloys that demonstrate tensile plasticity up to 10 % along with exceptionally high yield strength values reaching 1.5 GPa. These mechanical properties are achieved solely through standard technological processes, including homogenization, hot forging, cold rolling, and tempering/aging. This accomplishment is realized by leveraging the high-entropy/multiprinciple element approach, leading to the formation of a duplex-type cF4 and cI2 solid solution structure. The mechanical strengthening observed is a consequence of both dispersion strengthening with cI2 phase and deformation strengthening during the thermo-mechanical treatment applied. It is worth noting that this approach is versatile and can be extended to various other high-entropy-type alloys without strengthening intermetallic compounds. The effects of Cu addition, which is immiscible in Fe, on the resulting microstructure and oxidation heat resistance are also studied. Additionally, thermodynamic calculations are utilized to build phase diagrams for these multicomponent alloys.