Crack tip plasticity in silicon single crystals has been investigated using both high voltage electron microscopy (HVEM) and atomic force microscopy (AFM). Cracks were introduced into a (001) silicon wafer at room temperature by Vickers indentation method. The specimen temperature was increased to more than 873 K to activate dislocation generation around the crack tip under a residual stress due to the indentation. In specimens without the heat-treatment, no dislocations were observed around the crack, while in specimens with the heat-treatment, characteristic dislocation configurations were observed near the crack tip. AFM observations showed that slip bands were formed around the crack tip in the heat-treated specimens, and that the step heights of those slip bands were around one nanometer. Such crack tip plasticity is considered to be caused by mainly mode I tensile load, and contribute to increasing fracture toughness.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering