A History of the Fractography of Glasses and Ceramics

Quinn, George D.

doi:10.1002/9781118433010.ch1

Cited by 15 publications

(26 citation statements)

References 83 publications

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“…Fracture analysis was firstly performed by means of a binocular stereomicroscope (Discovery V20, Carl Zeiss, Göttingen, Germany) for determination of the spatial relationships of the observed fracture features [33,34]. The fragments were then cleaned in an ultrasonic bath (Ultrasonic CD-4820, Shenzhen Codyson Electrical Ltd, Guangdong, China) with isopropyl alcohol for 10 min, dried, and coated by gold-sputtering (Emitech SC7620, Quorum Technologies Ltd, Laughton, UK).…”

Section: Methodsmentioning

confidence: 99%

Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses

et al. 2017

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Objective This study evaluated the effects of two grading zirconia techniques on the fatigue limit of 3-unit fixed dental prostheses (FDPs). Methods Presintered blocks of 3Y-TZP were milled to obtain sixty-nine 3-unit FDPs, which were divided into three groups (n = 23). The control group (CTL) was sintered and glazed following manufacturer’s instructuctions. The two experimental groups presintered FDPs received a surface silica/glass infiltration treatment before the sintering process. Silica sol-gel group (SSG) was graded by the sol-gel processing route, while the glass-zirconia-glass group (GZG) was graded by an enameling technique. Graded groups did not receive a glaze layer after sintering. All FDPs were then luted with a dual-curing resin cement on composite abutments, embedded in polyurethane and stored in water for five days. The initial load of the fatigue test was calculated based on the results of the monotonic testing applied on three specimens of each group. To determine the fatigue limit, 20 samples of each group were subjected to staircase testing (100,000 cycles/5 Hz). Results The fatigue limits (in Newtons) were CTL = 1607.27, SSG = 1824.31, and GZG = 2006.57, and the Dixon and Mood test indicated statistically significant differences among groups (95% confidence interval). Significance The infiltration of silica and glass on bulk zirconia, by two different grading methods, increased the fatigue limits of monolithic zirconia FDPs.

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Section: Methodsmentioning

confidence: 99%

Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses

et al. 2017

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“…High-strength glasses are available (Varshneya, 2010;Wondraczek et al, 2011); however, even with chemical strengthening, they are still below the theoretical strength aimed for in defect-free conditions (Mattos, 2013). To approach the theoretical limit, understanding crack formation (Wiederhorn et al, 2013) and fracture behavior (Quinn, 2012;Bouchaud, 2013) is necessary. Further research should also aim to improve the ductility and fracture toughness of glass (Shi et al, 2014), which are intimately connected to the Poisson's ratio of the material (Greaves et al, 2011).…”

Section: Further Emphasis Onmentioning

confidence: 99%

Grand Challenges in Glass Science

Mauro

2014

Front. Mater.

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“…Following the Griffith criterion of brittle fracture, along with the corresponding specimen's failure stress, σ f , from the biaxial tests, a calculation of the critical stress intensity factor, K c , can be made as follows:

K_{c} = Y \cdot {normalσ}_{f} \cdot \sqrt{π \cdot a_{c}}

where Y is a geometric factor depending on the crack geometry and loading conditions. Due to the complicated crack morphology this factor may vary locally, but within bounds from Y = 0.7 for a semi elliptical crack to Y = 1.12 for surface cracks with 100 μm length and a depth of ~3 μm . Assuming a characteristic strength of ~280 MPa (Figure ) for both materials for scratched surfaces along the corresponding cleavage planes, and a critical crack size of ~2‐5 μm (Figures and ), a critical stress intensity factor of K c between 0.5 and 1.2 MPa·m 1/2 is obtained.…”

Section: Resultsmentioning

confidence: 99%

Understanding the effect of surface flaws on the strength distribution of brittle single crystals

et al. 2018

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The dependence of strength on the surface quality of brittle single crystals is highly relevant in microelectronic applications, where a certain roughening of the crystal surface is required to guarantee or enhance the functional properties of the final component. In this work, the effect of surface conditioning on the strength distribution of single crystals is assessed on LiTaO3 and LiNbO3 samples with distinct surfaces (i.e., polished, grinded, and scratched). Artificial surface cracks (scratches) were introduced using a Berkovich nanoindenter tip oriented under various angles with respect to the most critical {01true1false¯2} cleavage plane. Biaxial tensile tests were performed using the ball‐on‐three‐balls test, supported by fractographic analyses to interpret the strength results. A direct correlation between sub‐surface damage and strength was observed, associated with the hardness and elastic constants of the material, being strongly dependent on the crystal orientation with respect to the loading axis. Furthermore, we provide an explanation for the usually low Weibull modulus in single crystals and discuss the validity of the biaxial tests on scratched specimens for fracture toughness evaluation.

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A History of the Fractography of Glasses and Ceramics

Cited by 15 publications

References 83 publications

Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses

Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses

Grand Challenges in Glass Science

Understanding the effect of surface flaws on the strength distribution of brittle single crystals

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