Contributions of stress corrosion and cyclic fatigue to subcritical crack growth in a dental glass-ceramic
| Autor: | Jason A. Griggs, Yuanyuan Duan, Thomas J. Hill, Gaurav V. Joshi, Alvaro Della Bona, Kenneth R. St. John |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Dental Stress Analysis
Ceramics Cyclic stress Glass-ceramic Materials science Weibull modulus Fluorapatite Article law.invention Corrosion Stress (mechanics) Mechanics of Materials law visual_art Materials Testing visual_art.visual_art_medium General Materials Science Ceramic Composite material General Dentistry Beam (structure) |
| Zdroj: | Dent Mater |
| ISSN: | 0109-5641 |
| DOI: | 10.1016/j.dental.2014.05.026 |
| Popis: | Objective The objective of this study was to test the following hypotheses: (1) both cyclic degradation and stress-corrosion mechanisms result in subcritical crack growth (SCG) in a fluorapatite glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent) and (2) there is an interactive effect of stress corrosion and cyclic fatigue to accelerate subcritical crack growth. Methods Rectangular beam specimens were fabricated using the lost-wax process. Two groups of specimens ( N = 30/group) with polished (15 μm) or air-abraded surface were tested under rapid monotonic loading. Additional polished specimens were subjected to cyclic loading at two frequencies, 2 Hz ( N = 44) and 10 Hz ( N = 36), and at various stress amplitudes. All tests were performed using a fully articulated four-point flexure fixture in deionized water at 37 °C. The SCG parameters were determined using the ratio of inert strength Weibull modulus to lifetime Weibull modulus. A general log-linear model was fit to the fatigue lifetime data including time to failure, frequency, peak stress, and the product of frequency and logarithm of stress in ALTA PRO software. Results SCG parameters determined were n = 21.7 and A = 4.99 × 10 −5 for 2 Hz, and n = 19.1 and A = 7.39 × 10 −6 for 10 Hz. After fitting the general log-linear model to cyclic fatigue data, the coefficients of the frequency term ( α 1 ), the stress term ( α 2 ), and the interaction term ( α 3 ) had estimates and 95% confidence intervals of α 1 = −3.16 (−15.1, 6.30), α 2 = −21.2 (−34.9, −9.73), and α 3 = 0.820 (−1.59, 4.02). Only α 2 was significantly different from zero. Significance (1) Cyclic fatigue does not have a significant effect on SCG in the fluorapatite glass-ceramic evaluated and (2) there was no interactive effect between cyclic degradation and stress corrosion for this material. |
| Databáze: | OpenAIRE |
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