Chip formation behavior during ultrasonic vibration-assisted cutting of nickel-based superalloys

To address persistent challenges in conventional cutting (CC) of nickel-based superalloys—including pronounced serrated chip formation, elevated cutting forces, and accelerated tool wear—a coupled approach integrating molecular dynamics simulations with experimental ultrasonic vibration-assisted cutting (UVAC) was employed to systematically investigate chip formation mechanisms. A molecular dynamics model was developed to simulate UVAC of nickel-based superalloys, enabling atomic-scale characterization of chip morphology and defect evolution. Quantitative comparisons were conducted between CC and UVAC in terms of equivalent plastic strain distribution, von Mises stress fields, resultant cutting forces, and stacking fault energy variations. Complementary experimental validation was performed using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) to examine chip surface topography, subsurface microstructural features, and grain-level deformation responses under UVAC. The results indicate that UVAC causes the tool-workpiece interface to exhibit periodic contact-separation characteristics, leading to changes in the instantaneous undeformed chip thickness and cutting force. Compared with CC, under UVAC reduces the concentration of stress and strain, lowers the overall cutting force, and weakens chip serration. And the evolution of the atomic structure and the distribution characteristics of local defects in the chip formation zone are altered. The simulation and experimental results show that UVAC can significantly influence the chip formation behavior of nickel-based superalloys by modulating the cutting geometric relationship, contact state, and material plastic flow process.