Identification of crack path of inter- and transgranular fractures in sintered silicon nitride by in situ TEM

Seiichiro Ii, Chihiro Iwamoto, Katsuyuki Matsunaga, Takahisa Yamamoto, Yuichi Ikuhara

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    15 Citations (Scopus)

    Abstract

    Inter- and/or transgranular crack paths in sintered silicon nitride (Si3N4) during fracture were investigated by in situ straining experiments in a transmission electron microscope at room temperature, using a high-precision micro-indenter. By this technique, cracks introduced in an in situ manner were observed to propagate in the grain interior and along grain boundaries. High-resolution electron microscopy (HREM) observation revealed that the crack propagation takes place at an interface between Si 3N4 grains and an intergranular glassy film (IGF) in the case of intergranular fractures. According to the results by previous molecular dynamics simulations, a number of dangling bonds are present at the Si 3N4/IGF interface, which should result in the observed fracture behavior at the interface. On the other hand, the crack path introduced during transgranular fracture of Si3N4 grains was found to be sharp and straight. The observed crack propagated towards [1̄1̄20] inside the Si3N4 grain with the crack surface parallel to the (11̄00) plane. The HREM observations of crack walls revealed them to be atomically flat. The atomic termination of the crack walls was identified in combination with image simulations based on atomic models of the cleaved crack walls.

    Original languageEnglish
    Pages (from-to)121-127
    Number of pages7
    JournalJournal of Electron Microscopy
    Volume53
    Issue number2
    DOIs
    Publication statusPublished - 2004

    Keywords

    • Intergranular fracture
    • Silicon nitride
    • Transgranular fracture
    • Transmission electron microscopy
    • in situ observation

    ASJC Scopus subject areas

    • Instrumentation

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