Creep mechanisms and microstructural evidence of nanocrystalline CoCrFeMnNi

Creep property is an important mechanical parameter for the application of high-entropy alloys at high temperatures. In this work, the creep behavior of nanocrystalline CoCrFeMnNi was investigated using molecular dynamics simulations. The effects of temperature, stress and grain size on creep properties were discussed, and the microstructural evolution and deformation mechanisms were analyzed. The creep activation energy and diffusion activation energy were compared based on thermodynamics theory to further understand the creep mechanisms. The results showed that the creep mechanism is diffusion creep at low temperature and low stress. With the increase of temperature and stress, the creep mechanism changes to grain boundary slip or even dislocation motion. Grain size also affects the creep behavior. Finally, the creep properties of the high entropy alloy were compared with that of Ni, and it was found that the creep resistance of the high entropy alloy is better than that of Ni.