晶粒尺寸对多晶铜接触力学特性的影响

In order to study the influences of the grain sizes on the contact mechanics properties of the materials, the contact and separation processes of the diamond indenter and the copper substrate with different grain sizes were investigated at the atomic scale, where the molecular dynamics method was utilized and the elastoplastic deformations of the polycrystalline copper substrates were considered. The results show that with different grain sizes, the maximum adhesion force during the adhesive contact processes of the polycrystalline coppers remains unchanged basically, and the maximum normal contact force shows a trend of first increasing and then decreasing with the decrease of the grain sizes. Moreover, the nano-hardness and contact stiffness are respectively related to the changes of the plastic energy and elastic energy during the contact processes, and the change of the nano-hardness possesses a negative relation with that of the contact stiffness generally. Finally, based on common neighbor analysis method, a study of the elastoplastic deformation processes of the polycrystalline copper substrates was conducted, and it is found that the number of grain boundaries strongly influences the nano-hardness of materials, and then further affects the contact mechanics properties.