Size-dependent mechanical properties in CoCrFeNiMn crystalline/amorphous dual-phase high-entropy alloys nano-laminates

WB Yang and MR An and Q Deng and MJ Su and HY Song, MATERIALS TODAY COMMUNICATIONS, 48, 113626 (2025).

DOI: 10.1016/j.mtcomm.2025.113626

In current work, the influence of polycrystalline grain sizes (d) and amorphous layer thicknesses (h(a)) on the mechanical properties and plastic deformation mechanisms of CoCrFeNiMn crystalline/amorphous (C/A) dual-phase high-entropy alloys (HEAs) nano-laminates are investigated by molecular dynamics simulation. The results indicate that d and h(a) can influence the mechanical properties and plastic deformation mechanisms of C/A dual-phase HEAs nano-laminates. For the samples with constant amorphous thickness (h(a) = 2.5 nm), Young's modulus and average flow stress show an inverse Hall-Petch relationship with decreasing d. The deformation mechanism turns from the internal grain-dominated to grain boundary-dominated with decreasing d in the crystalline part, while uniform shear transformation zones (STZs) form in the amorphous layer. In addition, the smaller amorphous layer can hardly affect the mechanical properties of C/A dual-phase HEAs nano-laminates at d = 7.3 nm, which have even been destroyed during stretching. The crystalline layer dominates the deformation through the thickening of grain boundaries and FCC.HCP phase transformation. As h(a) increases, uniformly STZs distribute in the amorphous layer, and more stable average flow stress can be observed. The plastic deformation of the nano-laminates is affected by uniform STZs in the amorphous part and FCC -> HCP phase transformation in the crystalline part synergistically. The results will provide theoretical guidance for the design and application of CoCrFeNiMn HEA.

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