The size effect in microindentation

Nabarro, F. R. N.; Shrivastava, S.; Luyckx, S.

doi:10.1080/14786430600577910

Cited by 31 publications

(21 citation statements)

References 7 publications

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“…For example, Roebuck et al [35] reported an order of magnitude increase in the hardness of WC-11 wt.% Co when tested at 1 mN vs. its macro-hardness value. In a less extreme range of indenter sizes, Nabarro et al [36] indented a WC-11 wt.% Co sample over a load range of about 50 mN-10 N, and observed a hardness rise of about 50%, i.e., a similar increase to the present study, for a similar load change (200-fold vs. 600-fold for our study). Thus, the indenter size effect in WC-FeCr materials appears to be roughly in keeping with similar materials indented across a comparable range of loads.…”

Section: Coating Hardnesssupporting

confidence: 87%

Structure and Properties of High-Hardness Silicide Coatings on Cemented Carbides for High Temperature Applications

Humphry-Baker

Marshall

2018

Coatings

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Cemented tungsten carbides (cWCs) are routinely used in mining and manufacturing but are also candidate materials for compact radiation shielding in fusion power generation. In both applications, there is a need for oxidation to be minimized at operating temperatures. In a recent study, Si-based coatings deposited by pack cementation were demonstrated to improve the oxidation resistance of cWCs by up to a factor of 1000. In this work, these coatings are further characterized, with the focus on growth kinetics, phase composition, and hardness. By combining quantitative X-ray diffraction, electron microscopy, and instrumented micro-indentation, it is shown that the coating layer has a 20% higher hardness than the substrate, which is explained by the presence of a previously-unknown distribution of very hard SiC laths. To interpret the coating stability, a coating growth map is developed. The map shows that the structure is stable under a broad range of processing temperatures and cWC compositions, demonstrating the wide-ranging applicability of these coatings.

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Section: Coating Hardnesssupporting

confidence: 87%

Structure and Properties of High-Hardness Silicide Coatings on Cemented Carbides for High Temperature Applications

Humphry-Baker

Marshall

2018

Coatings

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“…On the other hand, orientation dependence of hardness for WC single crystals, although being established [12][13][14][15][16][17][18][19], is usually not considered in the referred studies. Possible reason for such treatment is the continuous recalling of indentation size effects on microhardness or nanohardness measurements [3,[17][18][19][20][21][22], a phenomenon that may somehow question the effective relevance of this hardness anisotropy for better modelling or analytical outcomes.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic hardness of constitutive phases in WC–Co composites: Nanoindentation testing, statistical analysis, WC crystal orientation effects and flow stress for the constrained metallic binder

Roa

Jiménez-Piqué

Verge

et al. 2015

Journal of the European Ceramic Society

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“…It is well known that hardness varies (usually, increases) with decreasing load or indentation depth for many materials; this phenomenon has been called the indentation size effect (ISE). Several theories have been proposed to explain the ISE, of which probably the most popular is the gradient plasticity theory, wherein geometrically necessary dislocations (GNDs) are generated under the indenter due to strain gradients [68][69][70]. Decreasing the indentation size results in a greater density of GNDs and hence in higher measured hardness.…”

Section: Micro/nanoindentationmentioning

confidence: 99%

Small-Scale Mechanical Testing of Cemented Carbides from the Micro- to the Nano-Level: A Review

Naughton-Duszová

Csanádi

Sedlák

et al. 2019

Metals

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In this overview, we summarize the results published to date concerning the small-scale mechanical testing of WC–Co cemented carbides and similar hardmetals, describing the clear trend in the research towards ever-smaller scales (currently at the nano-level). The load-size effect during micro/nanohardness testing of hardmetals and their constituents and the influence of the WC grain orientation on their deformation, hardness, indentation modulus, fracture toughness, and fatigue characteristics are discussed. The effect of the WC grain size/orientation, cobalt content, and testing environment on damage accumulation, wear mechanisms, and wear parameters are summarized. The deformation and fracture characteristics and mechanical properties, such as the yield and compression strength, of WC–Co composites and their individual WC grains at different orientations during micropillar compression tests are described. The mechanical and fracture properties of micro-cantilevers milled from WC–Co hardmetals, single WC grains, and cantilevers containing WC/WC boundaries with differently-oriented WC grains are discussed. The physical background of the deformation and damage mechanisms in cemented carbides at the micro/nano-levels is descri and potential directions for future research in this field are outlined.

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The size effect in microindentation

Cited by 31 publications

References 7 publications

Structure and Properties of High-Hardness Silicide Coatings on Cemented Carbides for High Temperature Applications

Structure and Properties of High-Hardness Silicide Coatings on Cemented Carbides for High Temperature Applications

Intrinsic hardness of constitutive phases in WC–Co composites: Nanoindentation testing, statistical analysis, WC crystal orientation effects and flow stress for the constrained metallic binder

Small-Scale Mechanical Testing of Cemented Carbides from the Micro- to the Nano-Level: A Review

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