Microstructure evolution and deformation mechanism of amorphous/crystalline high-entropy-alloy composites

High-entropy amorphous alloys present high hardness, but low tensile ductility. Here, deformation behavior of the amorphous/crystalline FeCoCrNi high-entropy alloy (HEA) composite prepared by the previous experiment is investigated using atomic simulations. The result shows the partial dislocations in the crystal HEA layer, and the formation of shear bands in the amorphous HEA layer occurs after yielding. The strength of the amorphous/crystalline HEA composite reduces with increasing the thickness of the amorphous layer, agreeing with the previous experiments. The coupled interaction between the crystal plasticity and amorphous plasticity in amorphous/crystalline HEA composites results in a more homogeneous redistribution of plastic deformation to cause interface hardening, due to the complex stress field in the amorphous layer. The current findings provide the insight into the deformation behavior of the amorphous/crystalline HEA composite at the nanoscale, which are useful for optimizing the structure of the HEA composite with high strength and good plasticity.