Precise design strategy of FeNiCrMo eutectic high-entropy alloys

A group of low-cost Fe40Ni(50-x)Cr10Mox high-entropy alloys (HEAs) without the Co element were proposed. The microstructure and properties were investigated. With the increase of Mo content, the microstructure changes from FCC single-phase to two-phase divorced eutectic, divorced eutectic + hypoeutectic, hypoeutectic, eutectic and hypereutectic, in which the two-phase is composed of FCC phase + s phase. The yield strength of alloy increases with the increase of Mo content. Its strengthening mechanism transforms from solution strengthening to second phase strengthening and grain boundary strengthening. Mo-20 and Mo-22.5 have comprehensive mechanical properties, and their yield strength, fracture strength and plastic strain are 1103.1 MPa and 1127.9 MPa, 1924.5 MPa and 1881.7 MPa, 30.4% and 28.7% respectively. In addition, the revised equivalent Cr content (ECC) is proposed in the FeNiCrMo HEAs, ECC = at.%[Cr]+8/3 x at.%[Mo]. The eutectic composition can be precisely designed through the revised ECC and atomic content ratio (RI/F) of the intermetallic forming elements to the FCC forming elements in FeNiCrMo HEAs system. When 20 at.%<= Fe and Ni <= 40 at.%, and RI/F = ECC/[x x at.%Fe + y x at.% Ni] = 1.05 +/- 0.3, FexNiyCrmMon is the eutectic high-entropy alloy.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

A study was conducted on low-cost Fe40Ni(50-x)Cr10Mox high-entropy alloys, showing that microstructure and properties change with the increase of Mo content, leading to a transformation in strengthening mechanism.