Reaction induced elastoplastic deformation and interlayer cracking during oxidation in copper nanowires

Copper nanowires have attracted significant attention for their potential applications in optics, electronics, and catalysis. However, the oxidation of nanowires in service devices can result in severe interlayer cracking, which compromises structural reliability. A detailed investigation is needed to accurately characterize the coupled processes of oxidation, plastic deformation and internal stress, as well as to assess the failure risk of interlayer cracking in nanowires. Here we developed a unified chemo-mechanical coupling model which incorporated oxidation process, oxygen ion diffusion, large plastic deformation and interlayer cracking. A robust finite element program was implemented to model the oxygen ion concentration and stress distribution during oxidation. Cohesive elements were employed to simulate the interlayer cracking behavior of copper nanowires. The results showed that shifts circumferential stress on the nanowire surface from compression to tension. Additionally, higher energy release rates shift the fracture location closer to the nanowire center. These findings advance the understanding of mechanical mechanisms underlying hollow nanostructure formation through oxidation, with implications for other fields involving chemo-mechanical coupling.