Microstructural deformation and amorphization behavior of silver during ultra-precision cutting: Atomic-scale insights and experimental verification

Abstract

Ultra-precision cutting, which employs diamond tools with nanoscale edge sharpness, is a promising technique for inducing extreme plastic deformation in metallic materials. In this work, pure silver is selected as a model material to explore the mechanical behavior and microstructural evolution under such severe deformation conditions. A combined approach of molecular dynamics (MD) simulations and transmission electron microscopy (TEM) is adopted to investigate the deformation mechanisms at the atomic and microstructural levels. The formation and evolution of V-shaped stacking faults and dislocation structures during the cutting process are systematically studied and experimentally validated. The influence of shear rate and hydrostatic pressure on the deformation behavior and defect generation is also examined. A detailed analysis of cutting forces and surface morphology is performed, while the subsurface amorphization of pure silver is characterized under various cutting parameters. Ultra-precision cutting experiments are conducted, and the resulting subsurface microstructure is observed via TEM. The simulation and experimental results show a high degree of consistency, confirming the reliability of the MD model in capturing the fundamental deformation mechanisms. The study reveals that the localized high-pressure and high-shear-strain fields induced by the diamond tool play a critical role in promoting the formation of stacking faults and amorphous regions in pure silver. These findings contribute to a deeper understanding of the microstructural evolution of metals under extreme mechanical loading and provide a theoretical basis for optimizing ultra-precision machining processes.