Atomic-scale study of ultrasonic elliptical vibration-assisted cutting of InP crystals via molecular dynamics

The ultrasonic elliptical vibration-assisted machining has proven effective in enhancing the machinability of brittle materials. To elucidate its influence on the removal mechanism of InP crystals, the molecular dynamics (MD) model of ultrasonic elliptical vibration-assisted cutting (UEVC) was established. The effects of normal amplitude and ultrasonic frequency on the cutting forces, thermo-mechanical responses, material removal behavior, and microstructural evolution of InP crystals were systematically analyzed. The results show that the cutting force in UEVC exhibits periodic “peak-valley” fluctuations. Although the instantaneous loads are higher, the average cutting force is markedly lower than that in conventional cutting (CC). UEVC leads to higher temperatures and local stresses, while large amplitudes effectively reduce shear strain. The proper parameter selection enhances both removal efficiency and surface quality. The periodic loading suppresses dislocation nucleation and propagation, resulting in a dominant 1/6 dislocation type and a substantial decrease in subsurface damage depth. Therefore, the intermittent “contact-separation” mechanism in UEVC improves InP machining efficiency and surface integrity while mitigating microstructural damage, offering theoretical guidance for low-damage machining of brittle materials.