Direct Measurement of Crack Tip Stresses

Andrew G. Haerle, W. Roger Cannon, Mitsunori Denda

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Abstract

Raman microprobe spectroscopy was used to measure the crack tip stress distribution in single‐crystalline silicon using a wedge‐loaded double cantilever beam (dcb) specimen. The wedge was advanced until the crack just propagated. After the crack arrested, the stresses were measured between 3 and 20 μm directly ahead of the crack. An average value of –0.43 was obtained for the slope of log stress vs log distance from the crack tip, rather than the theoretical value of –0.5. The value of KI was determined from (1) the intercept of this curve and (2) the slope of stress against . The values were in good agreement. The average experimental value of KI was determined to be 0.71 MPa · m1/2, compared to literature values for the KIC ranging from silicon of 0.8 to 0.94 MPa · m1/2. The value measured with the Raman is the arrest value of KI and is expected to be lower from kinetic energy considerations associated with wedge‐loaded dcb specimens.

Original languageEnglish (US)
Pages (from-to)2897-2901
Number of pages5
JournalJournal of the American Ceramic Society
Volume74
Issue number11
DOIs
Publication statusPublished - Nov 1991

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All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

Keywords

  • Raman spectroscopy
  • crack tip
  • silicon
  • single crystals
  • stress

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