Decomposition of the single-phase high-entropy alloy CrMnFeCoNi after prolonged anneals at intermediate temperatures

Lattice Distortions in the FeCoNiCrMn High Entropy Alloy Studied by Theory and Experiment

“…The bulk sample was mechanically ground into a 15 µm-thick ribbon, with SiC abrasive paper down to P4000. Chemical analysis revealed a nearly equi-atomic composition of Fe Recent findings showed phase decomposition in the FeCoNiCrMn alloy [29], and we, therefore, probed the compositional homogeneity at the atomic scale using atom probe tomography (LEAP 5000 XS, Cameca Inc., Düsseldorf, Germany) to verify a single-phase solid solution in the present samples. The results shown in Figure 1 reveal no indication of any compositional decomposition on the nm-scale.…”

Phase separation of metastable CoCrFeNi high entropy alloy at intermediate temperatures

“…Although all previous results have revealed that the CoCrFeNi base is stable, the very recent evidence shows that the CoCrFeMnNi HEA is unstable at intermediate temperatures [35,36], which brings great challenges to the HEA community. Almost at the same time, by using XRD and neutron diffraction, Dahlborg et al [37] claimed that the CoCrFeNi alloy should have two fcc phases with a discrepancy of 0.001Å in lattice parameter.…”

“…Another reason for the formation of σ phase is that, the Cr element is a strong σ phase former which can be proved by that all the binary phase diagrams of Cr-Co, Cr-Ni and Co-Fe have σ phase zones [36].…”

“…At high temperatures, the high mixing entropy effect [36] be thermally stable by TEM, APT, high energy x-ray scattering and neutron scattering [4,11].…”

Strong and Ductile Non-equiatomic High-Entropy Alloys: Design, Processing, Microstructure, and Mechanical Properties

“…[1][2][3][4][5][6] A large number of studies in this field have been motivated by the original HEA concept, which suggested that achieving maximized configurational entropy using equiatomic ratios of multiple principal elements could stabilize singlephase massive solid-solution phases. 1 However, an increasing number of studies have revealed that formation of single-phase solid solutions in HEAs shows weak dependence on maximization of the configurational entropy through equiatomic ratios of elements, [7][8][9][10] and it was even found that maximum entropy is not the most essential parameter when designing multicomponent alloys with superior properties. 11,12 These findings encouraged efforts to relax the unnecessary restrictions on both the equiatomic ratio of multiple principal elements as well as the formation of single-phase solid solutions.…”