Mechanism of Grain and Twin Nanoboundaries Making Strength and Wear Resistance Different in CoCrFeNiCu: A Molecular Dynamics Study

With the indenter scratches the single-crystal, polycrystalline and polycrystalline-twin structures CoCrFeNiCu, these characteristics in various crystal nanostructures were found. Single-crystal structure CoCrFeNiCu has the strongest strength, but its wear resistance is weakest in the three types for the generating of long-range and same direction hexagonal closest packings (HCPs), because the long-range HCPs will move the internal atoms, making single-crystal structure CoCrFeNiCu has the most serious abrasive wear. However, the multigrain boundaries can isolate the damage of scratching, playing a lubrication role. Twin-polycrystalline CoCrFeNiCu has the best wear resistance in the three structures because of the hardening effects of twin boundaries. Our relevant research results can not only deeper the understanding about the different structural effects on the wear resistance mechanism of high-entropy alloys, but also provide the guidance for the material structure applications.