A Simple Method for Determining Elastic‐Modulus–to‐Hardness Ratios using Knoop Indentation Measurements

Marshall, D. B.; Noma, Tatsuo; Evans, A.G.

doi:10.1111/j.1151-2916.1982.tb10357.x

Cited by 491 publications

(163 citation statements)

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“…12,18 The useful load range is relatively limited, and the hardness variations due to load dependence will probably be small in comparison with variations caused by experimental errors. 20,21 Only Knoop hardness was significantly higher for superficial than for deep dentin. The chief characteristic of the Knoop hardness test is its sensitivity to surface effects and textures.…”

Section: Discussionmentioning

confidence: 91%

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Microhardness of superficial and deep sound human dentin

Fuentes

Toledano

Osorio

et al. 2003

J Biomedical Materials Res

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Our purpose in this study was to determine the microhardness of superficial and deep dentin by means of two indentation methods (Knoop and Vickers) under two different applied loads. Twelve dentin discs approximately 2-mm thick were obtained from both superficial and deep dentin by transversally sectioning the crowns of sound, extracted human third molars with a diamond blade under water irrigation. Dentin surfaces were sequentially polished, and indentations (n ϭ 20 per surface) were performed with either Vickers indentor at loads of 300 and 500 g, respectively, or Knoop indentor at loads of 50 and 100 g, respectively. Average Vickers hardness number (VHN) and Knoop hardness number (KHN) were calculated and treated with two-way analysis of variance (ANOVA) and Student's t test. Microhardness of dentin was not influenced by the different loads applied for both indentation methods. Knoop hardness was significantly higher for superficial than for deep dentin (p Ͻ 0.05).

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Section: Discussionmentioning

confidence: 91%

“…12 For Knoop hardness, upon unloading, elastic recovery occurs mainly along the shortest diagonal and depth, but the longest diagonal remains relatively unaffected. 19,20 Therefore, the hardness measurements obtained by this method are practically insensitive to the elastic recovery of the material.…”

Section: Discussionmentioning

confidence: 99%

Microhardness of superficial and deep sound human dentin

Fuentes

Toledano

Osorio

et al. 2003

J Biomedical Materials Res

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“…La microdureza HV del recubrimiento fue hallada a partir de indentaciones realizadas con un indentador Vickers y el módulo de elasticidad fue calculado usando el método de Marshall [26], el cual se basa en el análisis de la huella residual producida con un indentador Knoop.…”

Section: Microindentaciónunclassified

Estudio de la estructura y las propiedades mecánicas en un recubrimiento de circona estabilizada con 8% en mol de itria elaborado por proyección térmica por plasma a partir de suspensiones

et al. 2016

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Estudio de la estructura y las propiedades mecánicas en un recubrimiento de circona estabilizada con 8% en mol de itria elaborado por proyección térmica por plasma a partir de suspensiones Study of the structure and mechanical properties in 8 mol% yttria-stabilized zirconia coating manufactured by suspension plasma spraying RESUMENEl estudio de recubrimientos nanoestructurados fabricados mediante proyección térmica ha generado un gran interés en las últimas dos décadas debido a su considerable mejora en sus propiedades sobre todo en las propiedades físicas y mecánicas. Esta mejora resulta de reducir los tamaños de grano de su materia prima a escalas de 100 a 1000 veces más bajas comparadas con los recubrimientos convencionales microestructurados. Así, estos recubrimientos con estructuras a nivel nano y/o submicrométrica están empezando a ser usados en la industria gracias a sus sobresalientes propiedades y es fundamental el estudio de sus propiedades mecáni-cas para determinadas aplicaciones. En la actualidad, la indentación es la principal técnica de caracterización de recubrimientos y películas delgadas, a pesar de estar altamente influenciada por los defectos propios del recubrimiento en la vecindad de la indentación. La nanoindentación y la microindentación se presentan como la mejor opción para evaluar el comportamiento mecánico de estos recubrimientos nanoestructurados. Por esta razón, en este trabajo se analizó el efecto de la estructura de un recubrimiento de circona estabilizada con 8% en mol de itria (8YSZ) elaborado por proyección térmica por plasma a partir de suspensiones nanométri-cas (SPS) y su relación con sus propiedades mecánicas (dureza y módulo de elasticidad) medidas por las técnicas de nanoindentación y microindentación. El análisis de la estructura de la sección transversal mostró que el recubrimiento exhibe una estructura bimodal, la cual está compuesta por una zona con partículas nanométricas semifundidas (ZS) y lamelas con mayor grado de fusión (ZF). Los ensayos de nanoindentación mostraron una distribución de Weibull bimodal de sus propiedades mecánicas, la cual característica de este tipo de recubrimientos; mientras que la dureza (HV) y el módulo de elasticidad evaluados por microindentación, presentaron una distribución monomodal. Estos resultados de microindentación estuvieron influenciados por el área de contacto en las zonas indentadas en la estructura bimodal del recubrimiento. Palabras clave:Recubrimiento por plasma a partir de suspensiones (SPS), estructura, indentación, Distribución Weibull, recubrimiento 8YSZ. ABSTRACTThe study of nanostructured coatings manufactured by thermal spraying has generated a great interest in the last two decades due to their considerable improved properties especially in the physical and mechanical properties. This improvement is to reduce grain sizes of their raw materials at scales of 100-1000 times lower compared to conventional coatings (microstructured). Thus, these coatings structured at the nano and sub micrometric scale start to be used i...

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“…In 1980, Marshall et al [12] suggested to evaluate the elastic modulus of a material by considering the elastic recovery of a Knoop indentation. These authors had observed that the small diagonal, w', of the indent was shorter than the expected theoretical value, w, while the large diagonal, L, remains constant after the withdrawal of the indenter.…”

Section: Elastic Modulusmentioning

confidence: 99%

“…The second objective is to examine the validity of the interpretation of indentation results obtained by various indentation process and indenters (Knoop, Vickers and sphere). For the determination of the elastic modulus, Knoop indentation will be used within the objective to apply the Marshall's method [12] based on the elastic recovery of the indent. Then Vickers and spherical indenters will be used to determine the elastic modulus in the conditions of calibration stated above.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Porosity-Free Beta Tricalcium Phosphate (<i>β</i>-TCP) Ceramic by Sharp and Spherical Indentations

Chicot¹,

Tricoteaux²,

Lesage³

et al. 2013

NJGC

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Instrumented indentation has been developed for determining the mechanical properties of materials but an accurate determination of these properties requires attention on contact stiffness analysis, indentation size effect, elastic modulus mode of calculation, role of stress distribution around the indent and its introduction in expanding cavity models for tensile mechanical properties determination. In the present work, models for hardness, elastic modulus and plastic properties determination by indentation are briefly reviewed and applied for the characterization of a porosity-free β-TCP bioceramic. As a main result the elastic modulus is found to be equal to 162 GPa resulting from the application of different approaches based on the use of various sharp and spherical indenters. Additionally, Martens and contact macrohardnesses were found to be independent on the dwell-time and equals to 4.1 and 6.3 GPa, respectively. Finally, models based on Hollomon's and Ludwik's laws as well as expanding cavity models were critically analyzed in light of their capacity to determine the yield stress and to represent the behavior law of the material. As a main result, the yield stress of the β-TCP is found to be equal to 2 GPa.

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A Simple Method for Determining Elastic‐Modulus–to‐Hardness Ratios using Knoop Indentation Measurements

Cited by 491 publications

References 4 publications

Microhardness of superficial and deep sound human dentin

Microhardness of superficial and deep sound human dentin

Estudio de la estructura y las propiedades mecánicas en un recubrimiento de circona estabilizada con 8% en mol de itria elaborado por proyección térmica por plasma a partir de suspensiones

Mechanical Properties of Porosity-Free Beta Tricalcium Phosphate (<i>β</i>-TCP) Ceramic by Sharp and Spherical Indentations

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A Simple Method for Determining Elastic‐Modulus–to‐Hardness Ratios using Knoop Indentation Measurements

Cited by 491 publications

References 4 publications

Microhardness of superficial and deep sound human dentin

Microhardness of superficial and deep sound human dentin

Estudio de la estructura y las propiedades mecánicas en un recubrimiento de circona estabilizada con 8% en mol de itria elaborado por proyección térmica por plasma a partir de suspensiones

Mechanical Properties of Porosity-Free Beta Tricalcium Phosphate (&lt;i&gt;β&lt;/i&gt;-TCP) Ceramic by Sharp and Spherical Indentations

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Product

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Mechanical Properties of Porosity-Free Beta Tricalcium Phosphate (<i>β</i>-TCP) Ceramic by Sharp and Spherical Indentations