CONTACT DYNAMICS WITH ONSET OF PLASTICITY IN PROBING NANOSCALE THIN SOLID FILMS BY AFM AND NANOINDENTATION

摘要

This study is focused on the nanoscale AFManoindentation probing tip dynamics in scratching and indenting thin solid films of nanoscale, A model is developed to identify bifurcation conditions that define the stick-slip oscillation patterns of the AFM tip. The model incorporates the inelastic deformation in the contact dynamics. The study reveals that the local energy fluctuations as a function of the inelastic deformation, defect formation, material properties and contact parameters determine the stick-slip behavior of the AFM tip. In addition, the transient variation of the localized function at the adhesion junction makes the response nonlinear. By quantifying the relation between the bifurcation parameters and the oscillation behavior, this model prescribes the complex adhesion dynamics of the contacting solids at nanoscale. Specifically, the model identified the stick-slip behavior in relation to the inelastic deformation and the local potential variations, which enables the model to justify the experimental observations and the molecular dynamics simulation of the adhesion/ friction dynamics at the nanoscale contact.