Molecular dynamics (MD) simulation is an effective approach to reveal the atomic-scale details of the material removal mechanism in nanometric cutting. In this study, through a MD simulation, we analyze the effects of cutting speed and cutting depth on cutting force and subsurface deformation of the cerium–lanthanum alloy during nanometric cutting. The results illustrate that the dislocations, stacking faults, and phase transitions occur on the material subsurface during the cutting process. The dislocations are mainly Shockley partial dislocation, and increasing the temperature and pressure during the cutting process leads to the transformation of γ-Ce (FCC) into β-Ce (HCP) and δ-Ce (BCC). β-Ce is mainly distributed in the stacking fault area, while δ-Ce is distributed in the boundary area between the dislocation atoms and γ-Ce atoms. The cutting speed and cutting depth are important factors affecting the distribution of subsurface damage. A thicker subsurface deformed layer on the machined surface, comprising dislocations, stacking faults, and lattice defects, is generated with an increase in the cutting speed and cutting depth. Simultaneously, the cutting speed and cutting depth significantly affect the cutting force, material removal rate, and generated subsurface state. The fluctuations in the cutting force are related to the generation and disappearance of dislocations. The higher the cutting speed and the deeper the cutting depth, the more phase-transition atoms on the subsurface.

Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries, and they are thus an important material in the green-energy industry. However, these alloys have very strong chemical activity, and their surfaces are easily oxidized, leading to great difficulties in their application. To improve the corrosion resistance of cerium–lanthanum alloys, it is necessary to obtain a nanoscale surface with low roughness. However, these alloys can easily succumb to spontaneous combustion during machining. Currently, to inhibit the occurrence of fire, machining of this alloy in ambient air needs to be conducted at very low cutting speeds while spraying the workpiece with a large amount of cutting fluid. However, this is inefficient, and only a very limited range of parameters can be optimized at low cutting speeds; this restricts the optimization of other cutting parameters. To achieve ultraprecision machining of cerium–lanthanum alloys, in this work, an auxiliary machining device was developed, and its effectiveness was verified. The results show that the developed device can improve the cutting speed and obtain a machined surface with low roughness. The device can also improve the machining efficiency and completely prevent the occurrence of spontaneous combustion. It was found that the formation of a build-up of swarf on the cutting tool is eliminated with high-speed cutting, and the surface roughness (Sa) can reach 5.64 nm within the selected parameters. Finally, the oxidation processes of the cerium–lanthanum alloy and its swarf were studied, and the process of the generation of oxidative products in the swarf was elucidated. The results revealed that most of the intermediate oxidative products in the swarf were Ce3+, there were major oxygen vacancies in the swarf, and the final oxidative product was Ce4+.