Effect of microcracking on the fracture toughness and fracture surface fractal dimension of lithia-based glass-ceramics
- Univ. of Florida, Gainesville, FL (United States)
The effect of thermally induced microcracks on the fracture toughness and fractal dimension of fully crystalline lithia disilicate glass-ceramics was studied. The fracture toughness, K{sub IC}, for the nonmicrocracked lithia disilicate, 3.02 {+-} 0.12 MPa {center_dot} m{sup 1/2}, was significantly greater than the value of 1.31 {+-} 0.05 MPa {center_dot} m{sup 1/2} for the microcracked specimens. The fractal dimensional increment, D*, was 0.24 {+-} 0.01 for nonmicrocracked lithia disilicate specimens compared with a value of 0.18 {+-} 0.01 for the microcracked specimens. The relationship between K{sub IC} and D* implies that the two materials exhibit dissimilar fracture behavior of microstructural differences. Estimates of the characteristic length involved in the fracture process, a{sub 0}, indicate that the materials have an identical fracture process at the atomic level. This paper contradiction may be explained by the scale on which the measurements were taken. It is suggested that fractal analysis at the atomic level would yield equivalent D* values for the two different microstructures.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 136503
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 11 Vol. 78; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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