Nanocutting mechanism of multi-layered metallic nanowires

Structural precision is a pivotal determinant of the performance and reliability of nanodevices, and achieving high-precision fabrication is the core objective of the nanofabrication field. Nanocutting opens up novel avenues for constructing intricate nanostructures, exhibiting extensive application prospects. However, the micro-deformation behaviour during this process is characterized by strong coupling of multi-scale and multi-mechanism features, and its formation and evolution mechanisms remain insufficiently elucidated. In particular, the impact of strain rate on the stress distributions at heterogeneous interfaces and the cooperative deformation mechanism still lack systematic investigation. In this study, Au/Ag/Au nanowires are employed as the research subject, to systematically reveal the influence mechanisms of cutting direction and strain rate on atomic-scale evolution behaviours. The results indicate that morphological evolution is dominated by anisotropic constraint mechanisms, and that the cutting orientation directly dictates the variations in stress-release pathways. Under high strain rates, the stress distribution within the Ag layer becomes significantly non-uniform, triggering crack initiation at the Au/Ag interface and leading to pronounced strain localization. Concurrently, interlayer atomic migration manifests as a thermo-mechanical-defect-coupled driving process, in which strain-rate-induced dislocations serve as high-speed “pipe diffusion” channels. This research systematically clarifies the intrinsic correlation between the instability behaviour and interlayer diffusion in multi-layer metal systems under high strain rates, providing a theoretical foundation for the deterministic machining of nanostructures.