Exploring the nano-polishing mechanisms of Invar

With the rapid development of nano-polishing technology, ultra-precise micro-nano components require tighter tolerances for the surface engineering of the Invar alloy. Due to its low hardness and high chemical activity, it is a challenge to obtain high-quality surfaces with a nanometric finish for Invar, and the mechanical mechanism guiding the nano-polishing process is also hard to derive experimentally. In this work, we studied the key influencing factors on the nano-polishing behavior of Invar by molecular dynamics simulation, and experiments were conducted to verify the simulation results. Our findings indicate that higher polishing speed and shallower polishing depth with optimized rolling torque can lead to a reduction of the subsurface damage as well as an improvement in polishing efficiency and surface quality. The nano-polishing mechanism is revealed, showing that effective removal occurs only in the plowing regime and the cutting regime, which require sufficient rolling/sliding depths. Furthermore, an analytic removal theory was developed that excellently describes and predicts the polishing behavior of Invar. Present work can provide a basis and technical support for the achievement of ultra-smooth and low-damage Invar surfaces, facilitating their wide applications in various significant fields.