A Critical Evaluation of Indentation Techniques for Measuring Fracture Toughness: II, Strength Method

Chantikul, P.; Anstis, G. R.; Lawn, Brian R.; Marshall, D. B.

doi:10.1111/j.1151-2916.1981.tb10321.x

Cited by 924 publications

(335 citation statements)

References 13 publications

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“…19) Furthermore, a stable indentation crack growth in bending test developed by Lawn and modified by Dransmann was applied (labeled as "SIGB"). 20), 21) For the SIGB tests, samples were indented with 4 HV10 indents at a distance of 2 mm along the middle axis.…”

Section: Methodsmentioning

confidence: 99%

Tough to brittle transition with increasing grain size in 3Yb-TZP ceramics manufactured from stabilizer coated nanopowder

Kern¹,

Gadow²

2016

J. Ceram. Soc. Japan

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Tetragonal zirconia polycrystals (TZP) are ceramics combining high strength and fracture resistance which are applied in biomedical and engineering applications. In this study, a nanoscale monoclinic zirconia nanopowder was coated with 3 mol-% ytterbia via a wet chemical route. The powders obtained after calcination and milling were consolidated into dense samples by hot pressing at 12751500°C for 1 h at 50 MPa axial pressure. Microstructure phase composition and mechanical properties were determined. The materials were initially very fine grained and showed grain growth starting at sintering temperatures exceeding 1350°C. At low sintering temperatures bending strength values of 10001100 MPa were recorded along with high fracture resistance of >10 MPa√m. In the sintering temperature range between 13501375°C, a steep decline of toughness to a level of 6 MPa√m was observed. This decline in fracture resistance is accompanied by a drop in transformability of the tetragonal phase and grain growth. While TZP from coprecipitated powders tend to become tougher with sintering temperature and increasing grain size, materials from stabilizer coated powders showed an adverse tendency. The tough to brittle transition in the 3Yb-TZP studied was attributed to the elimination of the initial stabilizer concentration gradient in the tetragonal grains.

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Section: Methodsmentioning

confidence: 99%

Tough to brittle transition with increasing grain size in 3Yb-TZP ceramics manufactured from stabilizer coated nanopowder

Kern¹,

Gadow²

2016

J. Ceram. Soc. Japan

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“…Indentation experiments constitute a family of widely-used techniques to evaluate some properties such as fracture toughness (72)(73). Moreover, the general relationship between contact stiffness, the area of contact and the elastic properties of the materials has led to instrumented indentation being a fundamental tool for the mechanical characterization of materials (74)(75).…”

Section: Determination Of Fracture Parametersmentioning

confidence: 99%

Comportamiento mecánico de materiales cerámicos estructurales

Bueno¹,

Baudı́n²

2007

Bol. Soc. Esp. Ceram. Vidr.

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The use of ceramic materials in structural applications is limited by the lack of reliability associated with brittle fracture behaviour. In order to extend the structural use of ceramics, the design of microstructures which exhibit flaw tolerance due to toughening mechanisms which produce an increase in crack growth resistance during crack propagation has been proposed. This work is a review of the mechanical behaviour of structural ceramic materials and its characterisation. Firstly, the basic brittle fracture parameters and the statistical criteria to determine the probability of exceeding the safety factors demanded for a particular application are analysed. Then, the toughening mechanisms which can be developed in the materials through microstructural design as well as the mechanical characterisation of toughened ceramics are discussed. The experimental values of linear elastic fracture toughness parameters (critical stress intensity factor, K IC , and critical energy release rate, G IC ) are not intrinsic properties for toughened materials and depend on crack length and the loading system. In this work, the different mechanical parameters proposed to characterise such materials are reviewed. The following fracture parameters are analysed: work of fracture (γ WOF ), critical J-integral value (J IC ) and R-curve. For the determination, stable fracture tests are proposed in order to ensure that the energy provided during the test is no more than the necessary one for crack propagation.Keywords: Microstructure, Strength, Weibull modulus, Fracture toughness, Toughening mechanisms. Comportamiento mecánico de materiales cerámicos estructuralesEl uso de los materiales cerámicos en aplicaciones estructurales está limitado por la falta de fiabilidad asociada a su comportamiento frágil durante la fractura. Para extender su aplicación se ha propuesto el diseño de microestructuras que presenten tolerancia a los defectos debido a la actuación de mecanismos de refuerzo. Este trabajo es una puesta al día sobre el estudio del comportamiento mecánico de los materiales cerámicos estructurales y su caracterización. En primer lugar, se revisan los parámetros de fractura utilizados para caracterizar materiales frágiles y los criterios de control estadístico que permiten determinar la probabilidad de que se sobrepasen los factores de seguridad exigidos en cada aplicación. A continuación, se discuten los mecanismos de refuerzo que se pueden desarrollar en los materiales cerámicos a través del diseño microestructural. En los materiales cerámicos en los que la actuación de mecanismos de refuerzo conduce a un comportamiento significativamente distinto del puramente frágil, los parámetros derivados del tratamiento lineal elástico (factor crítico de intensidad de tensiones, K IC , y tasa crítica de liberación de energía, G IC ), determinados experimentalmente, dejan de ser propiedades intrínsecas del material, independientes del tamaño de grieta y el sistema de carga. El presente trabajo revisa los parámetros mecánicos propuestos para...

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“…Fracture toughness values were calculated using both the indentation-crack length 9 and indentation-strength 10 techniques. For the indentation-crack length technique, fracture toughness measurements were made at room temperature on unpoled specimens.…”

Section: Fracture Toughnessmentioning

confidence: 99%

Mechanical behavior, properties and reliability of tin-modified lead zirconate titanate.

Watson¹

2003

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The influences of temperature and processing conditions (unpoled or poled-depoled) on strength, fracture toughness and the stress-strain behavior of tin-modified lead zirconate titanate (PSZT) were evaluated in four-point bending. PSZT exhibits temperaturedependent non-linear and non-symmetric stress-strain behavior. A consequence of temperature dependent non-linearity is an apparent reduction in the flexural strength of PSZT as temperature increases. At room temperature the average stress in the outer-fiber of bend bars was 84 MPa, whereas, for specimens tested at 120°C the average failure stress was only 64 MPa. The load-carrying capacity, however, does not change with temperature, but the degree of deformation tolerated by PSZT prior to failure increased with temperature. 4 ACKNOWLEDGEMENTS

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A Critical Evaluation of Indentation Techniques for Measuring Fracture Toughness: II, Strength Method

Cited by 924 publications

References 13 publications

Tough to brittle transition with increasing grain size in 3Yb-TZP ceramics manufactured from stabilizer coated nanopowder

Tough to brittle transition with increasing grain size in 3Yb-TZP ceramics manufactured from stabilizer coated nanopowder

Comportamiento mecánico de materiales cerámicos estructurales

Mechanical behavior, properties and reliability of tin-modified lead zirconate titanate.

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