Effective indenter radius and frame compliance in instrumented indentation testing using a spherical indenter

Kang, Seung‐Kyun; Kim, Ju‐Young; Kang, Ingeun; Kwon, Dongil

doi:10.1557/jmr.2009.0358

Cited by 25 publications

(9 citation statements)

References 50 publications

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“…Similar influences of geometrical imperfections of spherical tips on the determination of the material properties have been reported by various researchers [17,19,21,27]. However, using nom of four different tips (130, 200, 260 and 300 µm) and the Oliver-Pharr approach, Herbert et al [18] were able to predict the elastic moduli of fused silica and Al 6061-T6 with reasonable accuracy.…”

Section: Measurement Of Elastic Moduli By Spherical Indentation Testingsupporting

confidence: 64%

“…However, imperfections in the curvature have to be expected due to complexities in the manufacturing process. Tip imperfection studies conducted to assess the deviation of the spherical curvature from the nominal tip radius can be found in [17,19,27]. One such study performed by Constantinidis et al [27] utilized two different techniques: a) Indentations on fused quartz and b) AFM imaging, to determine the tip imperfections.…”

Section: Tip Imperfection Studymentioning

confidence: 99%

“…Indentation with spherical tips has been widely applied to characterize the mechanical properties of metals, ceramics and polymers [7,8,10,11,[17][18][19][20][21][22][23][24][25][26][27][28][29]. Indentation experiments with spherical tips have the advantages of gradual increases in stresses and elastic deformation dominating the initial stages of indentation testing.…”

Section: Introductionmentioning

confidence: 99%

“…The nominal tip radius of a spherical tip is usually specified by the manufacturer. But, as with Berkovich tips, imperfections in the geometry of a spherical tip will always be present and assuming the specified nominal tip radius as the actual value can lead to erroneous results [17,19,21,27]. Consequently, tip imperfections have to be examined and its influence on the indentation results studied, especially at smaller indentation depths where small imperfections can strongly influence the measurements.…”

Section: Introductionmentioning

confidence: 99%

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Length scale effects in epoxy: The dependence of elastic moduli measurements on spherical indenter tip radius

Chandrashekar

Han

2016

Polymer Testing

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Significant increases in the measured elastic moduli with decreasing indentation depth have been previously found in various polymers by indentation tests with a Berkovich tip at micro-to nanometer length scales. These increases in the determined elastic moduli were related to second order displacement gradients which increase with decreasing depth when a conical tip is applied.When a spherical tip is applied, such depth dependence should not be present as the second order displacement gradients remain essentially unchanged with indentation depth. However, these gradients should be proportional to the radius of the spherical tip. To examine the notion of second order displacement gradient dependence in measurements of elastic moduli, indentation experiments are conducted on epoxy with spherical tips of different nominal radii. Accounting for tip imperfections, an increase in the determined elastic moduli is found with decreasing tip radius, which corroborates the notion of second order displacement gradient dependence. 250 µm nominal radii. To address tip imperfections, the tips are examined with fused silica as a reference material. The results of these experiments are discussed in view of other possible factors and interpretations. Experiments Sample preparationEpoxy samples were prepared by mixing the commercially available liquid epoxy resin, EPON 828 (bisphenol A-epichlorohydrin), as base agent with the curing agent EPIKURE 3223, diethylenetriamine (DETA). The epoxy resin (Momentive Specialty Chemicals, USA) and DETA (Momentive Specialty Chemicals, USA) were used in the sample preparation following a procedure identical to that followed in [10], except that a curing agent content of 9 phr (parts per hundred resin) was used in the sample preparation, as opposed to 20 phr. Indentation testingThe indentation experiments were conducted at room temperature of about 23 o C with spherical tips of 3, 10, 50 and 250 µm nominal radii on an Agilent G200 nanoindenter system equipped with XP and DCM heads. The 3, 10 and 50 µm radii tips were purchased from SYNTON-MDP AG (Nidau, Switzerland) and the 250 µm tip was purchased from Micro Star Tech (Huntsville, TX, USA). The 3 µm radius tip was mounted on the DCM head and the other three tips on the XP head. The XP and DCM heads have load limits of 500 mN and 30 mN, respectively, which correspondingly limit the maximum indentation depth. The indentation experiments were conducted in two stages: 1) Tip imperfection study using fused silica as the reference material.2) Determination of elastic moduli of the epoxy sample.

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Section: Measurement Of Elastic Moduli By Spherical Indentation Testingsupporting

confidence: 64%

Section: Tip Imperfection Studymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Length scale effects in epoxy: The dependence of elastic moduli measurements on spherical indenter tip radius

Chandrashekar

Han

2016

Polymer Testing

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“…As regards the measurement on metallic materials using spherical indentation, the effect indenter radius should be considered [116][117][118]. As the geometry of the spherical indenter is imperfect, the effective indenter radius at a given depth is different from the nominal radius.…”

Section: Pile-up or Sink-in Phenomenonmentioning

confidence: 99%

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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Contact morphology and constitutive equation in evaluating tensile properties of austenitic stainless steels through instrumented spherical indentation

et al. 2012

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Effective indenter radius and frame compliance in instrumented indentation testing using a spherical indenter

Cited by 25 publications

References 50 publications

Length scale effects in epoxy: The dependence of elastic moduli measurements on spherical indenter tip radius

Length scale effects in epoxy: The dependence of elastic moduli measurements on spherical indenter tip radius

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

Contact morphology and constitutive equation in evaluating tensile properties of austenitic stainless steels through instrumented spherical indentation

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