Abstract: The excellent mechanical properties of CrMnFeCoNi high entropy alloy make it have a broad engineering application prospect. The constitutive description of material mechanical behavior is very important for the safety assessment of its engineering service behavior, but the constitutive model describing the tensile fracture behavior of CrMnFeCoNi high entropy alloy is rarely reported. Based on the crystal plastic constitutive model, the intergranular fracture process of CrMnFeCoNi high entropy alloy under uniaxial tension is simulated by using Cohesive element to implant grain boundaries with damage mechanism in polycrystalline representative volume elements. The simulation results are in good agreement with the experimental stress-strain curves, and can accurately describe the stress decline process during fracture, indicating that the macroscopic response behavior and fracture failure behavior of materials can be effectively described by crystal plastic constitutive model and Cohesive constitutive model. Further analysis shows that the crack initiates from the stress concentration; with the continuous increase of strain, the crack propagates along the grain boundary, resulting in fracture; the random grain orientation has a significant effect on the crack initiation location and propagation path, but has almost no effect on the macroscopic tensile stress-strain curve.

Key words: CrMnFeCoNi high-entropy alloy, crystal plasticity finite element method, Cohesive element, fracture behavior, orientation effect