Mechanical Properties and Deformation Behaviors of Metastable Fe50Mn20Ni20Cr10 High-Entropy Alloy at Ambient and Cryogenic Temperatures

A single-phase FCC structure of the Fe50Mn20Ni20Cr10 high-entropy alloy (HEA) was fabricated by vacuum arc melting. The mechanical properties and deformation mechanisms at both ambient and cryogenic temperatures were systematically investigated. The results reveal that the Fe50Mn20Ni20Cr10 HEA exhibits an ultimate tensile strength of 763 ± 30 MPa and an elongation of 66 ± 3.2% at 77 K. These values represent 58% and 35% increases, respectively, when compared with the alloy’s tensile properties measured at ambient temperature. The significantly enhanced yield strength and sustained stable strain-hardening behavior owing to the deformation-induced twinning and phase-transformation capabilities at 77 K. The twinning-prone matrix is capable of inducing more pronounced twinning-induced plasticity (TWIP) effects, thereby contributing to superior ductility of the alloy. Owing to the significant enhancement in both strength and ductility at 77 K, this alloy provides a new perspective for the design of chemical composition and mechanical deformation behavior of high-performance HEAs used in low-temperature environments.