Stress intensity factor and crack propagation behavior of thin α-alumina

Hajime Matsuo, Yusuke Kaieda, Nobuhiro Kojima, Ken Ichi Ikeda, Satoshi Hata, Hideharu Nakashima

Research output: Contribution to journalArticlepeer-review


This paper reports the mechanical property and crack propagation behavior of thin ceramics. A method to evaluate the stress intensity factor, K I, of thin ceramics was proposed. Dependence of KI values on the average grain size, d, of thin α-alumina were measured by the method. KI values of thin α-alumina decreased with increasing d values from 4.3 μm to 15.2 μm, while the KI values were almost constant for 15.2 μm ≤d≤63.0 μm. The trend of KI values agreed with the dependence of fracture toughness, Kc, of bulk α-alumina. The thin α-alumina specimens after crack propagation were investigated by scanning electron microscopic electron back-scattered diffraction (SEM/EBSD) analysis. Branched cracks were hardly observed, regardless of grain size. The result indicates that the toughing mechanism do not occur in the thin α-alumina. Dependence of the transgranular fracture rate, F, and the crack deflection rate, D, on d were measured from the orientation distribution maps. However, the F values and the D values were independent of d and approximately constant. The F values and D values depend on d in bulk α-alumina. It indicates that the crack propagation behavior is varied by thinning α-alumina.

Original languageEnglish
Pages (from-to)24-29
Number of pages6
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Issue number1
Publication statusPublished - Jan 2010

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry


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