The effects of hydrogen on the mechanical properties of CoCrFeMnNi high-entropy alloy: Molecular dynamics simulation

The molecular dynamics model of the CoCrFeMnNi high-entropy alloy (HEA) is established using the large-scale atomic/molecular massively parallel simulator. The tensile behaviors of the CoCrFeMnNi HEA in a hydrogen environment are simulated, and the effects of hydrogen on the mechanical properties are studied. The modified embedded-atom method and Lennard-Jones potentials are employed to describe the interaction between hydrogen and metal atoms. The addition of hydrogen atoms leads to significant degradation in mechanical properties and deterioration of the microstructure in the CoCrFeMnNi HEA. Specifically, an increase in hydrogen content leads to a significant reduction in both the ultimate tensile strength and plasticity, which is attributed to the disruption of the original face-centered cubic (FCC) structure. The proportion of FCC structure decreases to 66.59% at a hydrogen content of 3.00%. Furthermore, the tensile deformation reveals that dislocation activity is primarily governed by Shockley partial dislocations. The presence of hydrogen facilitates the nucleation and proliferation of these dislocations at significantly lower strains than those in the hydrogen-free condition. This paper elucidates the anti-hydrogen embrittlement mechanisms of this HEA coating, thereby providing a theoretical foundation for developing more effective prevention strategies.