Investigation on tensile behaviors of diamond-like carbon films
LC Bai and N Srikanth and H Wu and Y Liu and B Liu and K Zhou, JOURNAL OF NON-CRYSTALLINE SOLIDS, 443, 8-16 (2016).
The lubrication performance of diamond-like carbon films is significantly influenced by their deformations under loading. However, their deformation mechanisms are unclear so far due to their nanoscale thicknesses and complex microstructures. In this study, these mechanisms are explored by investigating the tensile response of the DLC films via molecular dynamics simulations. The atomic strain localizations are observed, and the regions where they occur are dominated by sp(2) clusters. These clusters relax the film at small tensile-strains by releasing its residual energies. The sp(3)-sp(2) transitions are present at large tensile-strains and prefer to occur in the strain localized regions. This preference significantly improves the graphitization level in these regions and thus promotes the sp(2) clusters to propagate. The propagation severely damages the sp(3) networks and leads to the failure of the film. This research suggests that reductions of heterogeneities such as existences of large-sized sp(2) clusters may be useful to delay the film failure by suppressing the initial strain localizations. It is demonstrated that the propagation of sp(2) clusters for the DLC films can be induced by their deformation besides the high friction temperature in their wear tests. This demonstration can help to improve the understanding of their trigological mechanisms. (C) 2016 Elsevier B.V. All rights reserved.
Return to Publications page