A Study of the Effect of the Ion Exchange Strengthening Method on Macroflaws in Soda-Lime Glass.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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The work examines the strengthening effect of the ion exchange method of chemical tempering on two specific types of macroflaws, a thermally blunted crack and a sawcut, in soda-lime glass. The use of these macroflaws permitted a quantitative fracture mechanics analysis of the amount of strengthening produced, and a greater access for ion exchange at the flaw tip then could be afforded by a sharp crack. The specimens were treated for various lengths of time in a potassium nitrate bath at 365C. A double cantilever cleavage technique of measuring fracture surface energy was used to find G sub c, the strain energy release rate. The average increase in G sub c was found to be roughly linear reaching a maximum level of approximately 200 at twelve hours of treatment for the blunted crack specimen type, while a similar maximum of approximately 200 was reached at six hours of treatment for the sawcut specimen type. Author
- Ceramics, Refractories and Glass