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

Research output: Contribution to journalArticlepeer-review

16 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
Externally publishedYes

Keywords

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

ASJC Scopus subject areas

  • Instrumentation

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