Indentation crack shapes and their evolution during subcritical crack growth in ion-exchanged glasses
- Pennsylvania State Univ., University Park, PA (United States)
The influence of surface residual stress on indentation crack shape and its evolution during subcritical crack growth was studied in ion-exchanged soda-lime and sodium alumino-silicate glasses. Crack shapes were determined optically from crack-arrest markings which were generated on the fracture surfaces during crack extension. The shapes, both after indentation and subsequent subcritical growth, were found to be very different from the semielliptical shapes observed in stress-free glasses. It was observed that high residual surface compression pinned the cracks near the failure origin (indentation site) and the growth occurred totally below the surface. The influence of the extent and the magnitude of the surface compression on crack-shape evolution was examined. It was found that the depth of the crack in ion-exchanged glasses was larger as compared to stress-free glasses. Furthermore, the depth of the crack increased with an increase in the compression layer thickness.
- DOE Contract Number:
- FG02-86ER45252
- OSTI ID:
- 535643
- Report Number(s):
- CONF-950739--
- Country of Publication:
- United States
- Language:
- English
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