Abstract：Abstract: High-entropy alloys are a new type of alloys composed of several principal elements (usually ≥5) with equiatomic or near equiatomic ratios. Experimental studies have shown that the CrMnFeCoNi high-entropy alloy has higher tensile strength and fracture toughness at room temperature than at lower temperatures. In this paper, we performed molecular dynamics simulations to investigate the tensile behavior of the nanocrystalline CrMnFeCoNi alloy with an average grain size of 6 nm at 300, 200, and 77 K, respectively. The temperature effect and toughening mechanism of nano-scale CrMnFeCoNi high-entropy alloys were revealed. Microstructure evolution analyses show that in the plastic deformation stage at low temperatures, the slip systems were less activated. With the resistance of dislocation slip increases, the yield and tensile strengths increase. When the simulation cell collapses upon deformation, the nucleation of void defects is slower; More void defects evolve into fracture, and more fracture surfaces distribute tensile strain, which makes the low-temperature toughness of nanocrystalline high-entropy alloys better.
2020, Vol. 41 
