Molecular dynamics simulation of monocrystalline copper nano-scratch process under the excitation of ultrasonic vibration

In order to explore the mechanism of unidirectional ultrasonic vibration-assisted machining from a microscopic point of view, the molecular dynamic (MD) simulation method is used to simulate the scratch process of monocrystalline copper under ultrasonic excitation. By comparing the simulation results of traditional scratching and ultrasonic vibration-assisted scratching, the influences of ultrasonic vibration on the surface morphology, the tangential force, and the evolution of the crystal's internal defects are discussed. The results show that the ultrasonic vibration can improve the surface quality of the workpiece, reduce the tangential force, and reduce the energy consumption. Simultaneously, ultrasonic vibration promotes the interaction between dislocations, accelerates the annihilation of dislocations, effectively reduces work hardening caused by dislocation accumulation, and forms a large number of vacancies and interstitial atoms. (paper)