Analysis on multiple ring-like cracks in thin amorphous carbon film on soft substrate under nanoindentation

Kunkun Fu, Yongbai Yin, Li Chang, Dahua Shou, Bailin Zheng, Lin Ye

    Research output: Journal article publicationJournal articleAcademic researchpeer-review

    22 Citations (Scopus)


    In the present work, the fracture toughness of thin amorphous carbon films was quantitatively characterized by nanoindentation using a conical indenter. The amorphous carbon films with different thickness, i.e. 140 and 400 nm, were obtained by plasma vapour deposition on a poly-ether-ether-ketone substrate. During indentation, it was noticed that multiple ring-like, through-thickness cracks occurred in the films. Correspondingly, 'sliding pop-ins' were observed in the load-depth curves. Using an energy method, the fracture toughness of the films could be therefore determined. The results showed that the fracture toughness of the amorphous carbon films was in the range of 0.99-2.87 MPa m 0.5, which agreed well with the published data. Further, finite element analysis was also performed to evaluate the stress distribution in a thin film/soft substrate system, which showed that the ring-like cracks were caused by the tensile radial stress on the film surface.

    Original languageEnglish
    Article number505314
    JournalJournal of Physics D: Applied Physics
    Issue number50
    Publication statusPublished - 18 Dec 2013

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Acoustics and Ultrasonics
    • Surfaces, Coatings and Films


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