Analyzing crack-tip dislocations and their shielding effect on fracture toughness

K. Higashida, M. Tanaka, A. Hartmaier, Y. Hoshino

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

With the aim of experimental clarification of the interaction between a crack and dislocations, crack-tip dislocations in two kinds of plastic zones in silicon crystals were directly observed by high-voltage electron microscopy to analyse by their detail characterisation. Three-dimensional analysis on crack-dislocation interaction revealed that they were shielding type dislocations in both 45°-shear-type and hinge-type plastic zones, which accommodate mainly mode I stress intensity at the crack tip. The crack-tip shielding fields due to dislocations also have been visualised by photoelasticity. In specimens without pre-deformation, photoelastic images due to the mode I crack-tip field were observed when an external load was applied at room temperature. In specimens pre-deformed at high temperatures, photoelastic images corresponding to the dislocation shielding were observed. The shielding field has an effect of accommodating the tensile stress concentration due to the applied load, which increases the critical stress intensity factor for crack extension.

Original languageEnglish
Pages (from-to)13-18
Number of pages6
JournalMaterials Science and Engineering A
Volume483-484
Issue number1-2 C
DOIs
Publication statusPublished - Jun 15 2008

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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