Nanoindentation hardness of submicrometer alumina ceramics

Krell, Andreas; Schädlich, Stefan

doi:10.1016/s0921-5093(00)01818-9

Cited by 128 publications

(73 citation statements)

References 15 publications

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“…Within this objective, a variety of models describing the contact area function have been developed [20,[40][41][42][43][44][45][46][47]. In nanoindentation, the complex area function expressing the contact area as a function of the contact indenter displacement is probably the most used: where C 1 through C 8 are constants.…”

Section: Indentation On Massive Materialsmentioning

confidence: 99%

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Hemmouche¹,

Chicot²,

Amrouche³

et al. 2013

Materials Science and Engineering: A

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tThe elastic modulus of thin films can be directly determined by instrumented indentation when the indenter penetration does not exceed a fraction of the film thickness, depending on the mechanical properties of both film and substrate. When it is not possible, application of models for separating the contribution of the substrate is necessary. In this work, the robustness of several models is analyzed in the case of the elastic modulus determination of a porous aluminium oxide film produced by anodization of an aluminium alloy. Instrumented indentation tests employing a Berkovich indenter were performed at a nanometric scale, which allowed a direct determination of the film elastic modulus, whose value was found to be approximately 11 GPa. However, at a micrometric scale the elastic modulus tends toward the value corresponding to the substrate, of approximately 73 GPa. The objective of the present work is to apply different models for testing their consistency over the complete set of indentation data obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation. This approach shows the continuity between the two scales of measurement thus allowing a better representation of the elastic modulus variation between two limits corresponding to the substrate and film elastic moduli. Gao's function proved to be the best to represent the elastic modulus variation.

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Section: Indentation On Massive Materialsmentioning

confidence: 99%

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Hemmouche¹,

Chicot²,

Amrouche³

et al. 2013

Materials Science and Engineering: A

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“…[14][15][16][17][18][19][20][21] Instead of Eq. (1), two approximations of the loading curve have been elaborated: fitting by (i) power law or (ii) second-order polynomial.…”

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confidence: 99%

Depth-sensing indentation tests in studying plastic instabilities

et al. 2004

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This review surveys the phenomenon of plastic instabilities occurring in depth-sensing indentation measurements. Investigations presented focus on the characterization of Portevin-Le Châtelier type instabilities observed in different metal alloys during indentation. The effect of some important factors such as solute concentration, the formation of Guinier-Preston zones, and grain size and orientation are described and discussed. The phenomenon of plastic instabilities as serrated flow recently observed in bulk metallic glasses is also briefly reviewed. I. GENERAL APPLICATIONS OF DEPTH-SENSING INDENTATION METHODIn the last two decades, depth-sensing indentation (DSI) became widely used for the mechanical characterization of solids. The reason for its popularity is that DSI enables the determination of mechanical properties even for a small volume of material without complicated sample preparation. The DSI method is an improvement over conventional hardness measurement. The most important motivations of this development are the following: (i) the optical evaluation of extremely small indentations in hard materials and thin layers is very uncertain, (ii) the DSI enables the measurement of the depth profile of the hardness perpendicular to the surface in gradient materials, (iii) the method allows the study of changes in the hardness during deformation under load (dynamic hardness), and (iv) the penetration or the loading rate, which affect the hardness value, can be selected and controlled during indentation.During the DSI process, an indenter is penetrated into the surface of the material with constant indentation rate or loading rate. In the majority of the measurements, the loading rate is held constant. When the load reaches its selected maximum value, the load decreases with the same rate as for loading and the indenter moves backward. The load-penetration depth curves are recorded in both the loading and the unloading parts of the measurement as schematically shown in Fig.

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“…The most important surface mechanical property that defines the contact resistance of alumina is its hardness. Therefore, it is not surprising that hardness evaluation at various length scales consumes a significant amount of current research efforts in alumina [6][7][8][9][10][11][12][13][14]. Most of the commercially available alumina ceramics used for a variety of technical applications are coarse grained.…”

Section: Introductionmentioning

confidence: 99%

“…They exhibit low to moderate hardness and, in addition, characteristically exhibit an R-curve behaviour which means that their crack growth resistance improves as the crack grows. In spite of the wealth of literature that exists on hardness of alumina measured at macro-, microscale [10][11][12], or nanoscale [13,14] mostly for fine grain and/or submicrometer grain-sized alumina ceramics; however, the reports on hardness behaviour of dense coarse grained alumina ceramics are really rare [10]. It is important to recognize that depth sensitive indentation technique has emerged as a very effective technique to determine the surface mechanical properties of wide variety of materials [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Contact Deformation of Alumina

Bhattacharya

Mukhopadhyay

2012

ISRN Ceramics

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The study of contact-induced deformations during hardness evaluation and the subsequent damage mechanisms of alumina under low loads deserves significant importance for its applications as wear-resistant inserts, biomedical implants, thin films, and armour plates, because the contact-induced brittle failure is an issue of major scientific concern that prevents their widespread commercial applications. However, the studies on hardness of dense, coarse grain alumina at ultralow load, for example, 1 N, are still lacking. Therefore, the present study was conducted on a dense (∼95% of theoretical) coarse-grain (∼20 μm) alumina at a low peak load of 1 N with varying loading rates (10 −3 -10 0 N·s −1 ) applied in depth sensitive indentation experiments. The results showed profuse presence of multiple micro-pop-in and pop-out events possibly linked to dislocation nucleations underneath the indenter. The critical resolved shear stress (τ CRSS ) was found to enhance with the increase in applied loading rates. The occurrences of the localized shear deformation band formation and microcracking in and around the indentation cavity were explained in terms of the correlation between the nanoscale plasticity events, the small magnitude of (τ CRSS ), the maximum shear stress (τ max ) developed just underneath the indenter, and the dislocation loop radius (R d ).

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Nanoindentation hardness of submicrometer alumina ceramics

Cited by 128 publications

References 15 publications

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

An analysis of the elastic properties of a porous aluminium oxide film by means of indentation techniques

Depth-sensing indentation tests in studying plastic instabilities

Contact Deformation of Alumina

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