The correlation of indentation experiments

Johnson, Kenneth L.

doi:10.1016/0022-5096(70)90029-3

Cited by 1,257 publications

(700 citation statements)

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“…modulus, yield strength) of the material. Tabor (1951) and Johnson (1970) established relationships between hardness as measured by conical (or pyramidal) and spherical indenters and the stress-strain behavior in the regime of ''large'' indents for which conventional plasticity theory is applicable.…”

Section: Introductionmentioning

confidence: 99%

Discrete dislocation plasticity analysis of the wedge indentation of films

Balint¹,

Deshpande²,

Needleman³

et al. 2006

Journal of the Mechanics and Physics of Solids

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Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractThe plane strain indentation of single crystal films on a rigid substrate by a rigid wedge indenter is analyzed using discrete dislocation plasticity. The crystals have three slip systems at AE35:3 and 90 with respect to the indentation direction. The analyses are carried out for three values of the film thickness, 2, 10 and 50 mm, and with the dislocations all of edge character modeled as line singularities in a linear elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation are incorporated through a set of constitutive rules. Over the range of indentation depths considered, the indentation pressure for the 10 and 50 mm thick films decreases with increasing contact size and attains a contact size-independent value for contact lengths A44 mm. On the other hand, for the 2 mm films, the indentation pressure first decreases with increasing contact size and subsequently increases as the plastic zone reaches the rigid substrate. For the 10 and 50 mm thick films sink-in occurs around the indenter, while pile-up occurs in the 2 mm film when the plastic zone reaches the substrate. Comparisons are made with predictions obtained from other formulations: (i) the contact sizeindependent indentation pressure is compared with that given by continuum crystal plasticity; (ii) the scaling of the indentation pressure with indentation depth is compared with the relation proposed by Nix and Gao [1998

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Section: Introductionmentioning

confidence: 99%

Discrete dislocation plasticity analysis of the wedge indentation of films

Balint¹,

Deshpande²,

Needleman³

et al. 2006

Journal of the Mechanics and Physics of Solids

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“…From the curve of mean pressure versus load, Tabor [42] found that the initial yield point corresponding to the onset of plastic deformation which occurred when P m =1.1σ y . Johnson [6] proposed a dimensional parameter =E r /a( y /R) and proved theoretically that the elastic regime was valid up to =2.53. This regime is consistent with the Hertz elastic theory.…”

Section: Spherical Indentation Regimementioning

confidence: 99%

“…Researchers have extended the expanding cavity models (ECM) based on Hill's work for indentation with different indenter tips or indented materials [6][7][8]. For conical indentation, based on von Mises yield criterion and the assumption of material incompressibility, ECMs can be expressed as:…”

Section: Indentation On Elastic-plastic Materialsmentioning

confidence: 99%

“…Many pioneers have studied the spherical indentation regimes [6,[42][43][44][45][46][47][48][49][50]. Generally, the spherical indentation process can be divided into three distinct regimes: elastic, elastic-plastic and fully plastic (illustrated in Fig.…”

Section: Spherical Indentation Regimementioning

confidence: 99%

“…It should be emphasized that the representative strain defined in the Tabor equation is an average value. The strain constraint fact, , should vary with the depth of the indentation for which the tangent of corresponding contact point could be equal to the same angle of sharp indenter [6,55]. Most of researchers agreed with the formulation of Tabor's equation, but argued the choice of the value of  and  [56][57][58][59][60][61][62].…”

Section: Determination Of Plastic Property Through Spherical Indentatmentioning

confidence: 99%

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Determining the elastic-plastic properties of metallic materials through instrumented indentation

Chang¹

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AgradecimientosPrimero, me gustaria agradecer a mis supervisores. Me gustaría expresar mi máximo aprecio hacia mi supervisor Dr. J. Ruiz-Hervias por guiarme y ayudarme durante estos años en el laboratorio. He aprendido de él, no solo en lo estrictamente académico, si no en su generosidad y en su mente positiva hacia la vida. Además, también quería agradecer a mi co-supervisor Dr. M. A. Garrido. Él ha jugado un papel muy significante en el inicio de mi vida académica. Sus ideas y su entusiasmo siempre me inspiraron y me motivaron. Sin su paciencia y su ayuda, nunca hubiera acabado esta tesis. ResumenEn los últimos años, y asociado al desarrollo de la tecnología MEMS, la técnica de indentación instrumentada se ha convertido en un método de ensayo no destructivo ampliamente utilizado para hallar las características elástico-plásticas de recubrimientos y capas delgadas, desde la escala macroscópica a la microscópica. Sin embargo, debido al complejo mecanismo de contacto debajo de la indentación, es urgente proponer un método más simple y conveniente para obtener unos resultados comparables con otras mediciones tradicionales. En este estudio, el objetivo es mejorar el procedimiento analítico para extraer las propiedades elástico-plásticas del material mediante la técnica de indentación instrumentada.La primera parte se centra en la metodología llevada a cabo para medir las propiedades elásticas de los materiales elásticos, presentándose una nueva metodología de indentación, basada en la evolución de la rigidez de contacto y en la curva fuerza-desplazamiento del ensayo de indentación. El método propuesto permite discriminar los valores de indentación experimental que pudieran estar afectados por el redondeo de la punta del indentador. Además, esta técnica parece ser robusta y permite obtener valores fiables del modulo elástico.La segunda parte se centra en el proceso analítico para determinar la curva tensión-deformación a partir del ensayo de indentación, empleando un indentador esférico. Para poder asemejar la curva tension-deformación de indentación con la que se obtendría de un ensayo de tracción, Tabor determinó empíricamente un factor de constricción de la tensión () y un factor de constricción de la deformación (). Sin embargo, la elección del valor de  y  necesitan una derivación analítica. Se describió analíticamente una nueva visión de la relación entre los factores de constricción de tensión y la deformación basado en la deducción de la viii ecuación de Tabor. Un modelo de elementos finitos y un diseño experimental se realizan para evaluar estos factores de constricción. A partir de los resultados obtenidos, las curvas tension-deformación extraidas de los ensayos de indentación esférica, afectadas por los correspondientes factores de constricción de tension y deformación, se ajustaron a la curva nominal tensión-deformación obtenida de ensayos de tracción convencionales.En la última parte, se estudian las propiedades del revestimiento de cermet Inconel 625-Cr 3 C 2 que es depositado en el medio de una a...

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Processing and Hardness of Single Crystal Al2O3 Films Containing Nano-ZrO2 Inclusions Produced by Chemical Solution Deposition

McNally¹,

Lange

Marshall

1998

phys. stat. sol. (a)

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Single crystal, homoepitaxial α‐Al2O3 films containing nanoscale ZrO2 inclusions were grown on basal‐plane, sapphire substrate. The substrates were coated with an aqueous solution containing aluminium nitrate and zirconium acetate and heat treated at 1200 °C. Powders were also prepared from these precursors by spray pyrolysis and heat treatment. XRD and TEM analyses confirmed the expected nonequilibrium phase evolution from an amorphous inorganic to γ‐Al2O3 to γ‐Al2O3 + tetragonal ZrO2 to α‐Al2O3 + tetragonal ZrO2. Cross‐sectional TEM of the films confirmed homoepitaxy and the random spatial distribution of spherical, tetragonal ZrO2 inclusions approximately 20 nm in diameter. Nanoindentation studies show that these inclusions at 2, 5, and 15 vol% do not significantly affect the room temperature hardness of alumina.

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The correlation of indentation experiments

Cited by 1,257 publications

References 5 publications

Discrete dislocation plasticity analysis of the wedge indentation of films

Discrete dislocation plasticity analysis of the wedge indentation of films

Determining the elastic-plastic properties of metallic materials through instrumented indentation

Processing and Hardness of Single Crystal Al2O3 Films Containing Nano-ZrO2 Inclusions Produced by Chemical Solution Deposition

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