Hall-Petch relations for multilayered materials

Anderson, Peter M.; Li, C.

doi:10.1016/0965-9773(95)00250-i

Cited by 312 publications

(108 citation statements)

References 42 publications

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“…Such a tendency was previously confirmed on TiN/NbN superlattices by Yashar and Sproul [7] and by other authors [8,9] for different carbide and nitride PVD deposited superlattice coatings. Anderson and co-authors also observed a similar micro-hardness evolution for metallic structure like Cu/Ni multilayers [10]. They developed a complete model based on the calculation of the critical shear stress required for the dislocation loop moving within a given layer, and the determination of the dislocation density in the cell.…”

Section: Layered Structurementioning

confidence: 99%

Fretting wear analysis of TiC/VC multilayered hard coatings: experiments and modelling approaches

Fouvry¹,

Wendler

Liskiewicz

et al. 2004

Wear

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: TiC-VC multilayered hard coating were obtained using an original two step hard coating process. Xray analysis, micro-hardness measurements and GDMS's chemical profiles have been conducted to characterise, respectively, crystallography, hardness and multilayer structure as a function of the sub-layer thickness. It shows that although well TiC and VC carbide textures are maintained, a decrease of the sublayer thickness promotes inter-diffusion phenomena which progressively erase the alternated structure. The micro-hardness variation as a function of sublayer thickness displays a parabolic evolution with maximum hardness for a critical thickness around 50 nm. Consistent with the dislocation moving force theories, these results confirm that the micro-hardness evolution is function of the carbide grain size. Wear and friction properties have been studied under gross slip fretting conditions. A "composite" wear model, which considers the diffusion inter-layer, has been developed. Unlike classical rules of mixtures, the modulation dependence of wear and friction is here considered. Reliable wear rates as a function the modulation thickness can be predicted. The friction evolution is less easily predicted due to the smoothing effect of third body. Finally, the opposite evolution between wear resistance and micro-hardness is discussed, outlining the necessity of avoiding any direct prediction of a given tribological response from a plain micro-hardness measurement.

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Section: Layered Structurementioning

confidence: 99%

Fretting wear analysis of TiC/VC multilayered hard coatings: experiments and modelling approaches

Fouvry¹,

Wendler

Liskiewicz

et al. 2004

Wear

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“…Some decades later, Sproul et al 42 stated that several explanations have been proposed to explain the hardness increase, including not only the dislocation barrier due to the interface mismatch 43 but also the Hall Petch effect 44 . Additionally, coherent strain and the effect of different modulus of elasticity between sub-layers have been suggested as mechanisms that may contribute for hardness increase.…”

Section: Microhardness and Periodicitymentioning

confidence: 99%

Thick CrN/NbN Multilayer Coating Deposited by Cathodic Arc Technique

et al. 2016

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The production of tribological nanoscale multilayer CrN/NbN coatings up to 6 μm thick by Sputtering/HIPIMS has been reported in literature. However, high demanding applications, such as internal combustion engine parts, need thicker coatings (>30 µm). The production of such parts by sputtering would be economically restrictive due to low deposition rates. In this work, nanoscale multilayer CrN/NbN coatings were produced in a high-deposition rate, industrial-size, Cathodic Arc Physical Vapor Deposition (ARC-PVD) chamber, containing three cathodes in alternate positions (Cr/ Nb/Cr). Four 30 μm thick NbN/CrN multilayer coatings with different periodicities (20, 10, 7.5 and 4 nm) were produced. The coatings were characterized by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The multilayer coating system was composed of alternate cubic rocksalt CrN and NbN layers, coherently strained due to lattice mismatch. The film grew with columnar morphology through the entire stratified structure. The periodicities adopted were maintained throughout the entire coating. The 20 nm periodicity coating showed separate NbN and CrN peaks in the XRD patterns, while for the lower periodicity (≤10nm) coatings, just one intermediate lattice (d-spacing) was detected. An almost linear increase of hardness with decreasing bilayer period indicates that interfacial effects can dominate the hardening mechanisms.

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“…(1). Several recent experimental [1,3] and theoretical [4][5][6] studies have, however, shown that the H-P model may break down at nm-length scales. At µm-length scales, dislocation pile-ups can be treated as a continuum distribution and eq.…”

Section: Introductionmentioning

confidence: 99%

“…The assumption that the number of dislocations in the pileup (N) decreases in proportion with decreasing h provides one way to interpret the dependence of strength on h at nm-length scales [4,5]. In this approach, a peak in strength is reached when h is so small that N cannot exceed one [4,5]. This approach assumes that the dislocation sources are such that pile-ups will always form, whether N=2 or significantly greater.…”

Section: Introductionmentioning

confidence: 99%

Dislocation Models for Strengthening in Nanostructured Metallic Multilayers

et al. 2000

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Ultra-high strength metallic multilayers are ideal for investigating the effects of length scales in plastic deformation of metallic materials. Experiments on model systems show that the strengths of these materials increase with decreasing bilayer period following the Hall-Petch model. However, as the layer thickness is reduced to the nm-scale, the number of dislocations in the pile-up approaches one and the pile-up based Hall-Petch model ceases to apply. For nm-scale semi-coherent multilayers, we hypothesize that plastic flow occurs by the motion of single dislocation loops, initially in the softer layer, that deposit misfit type dislocation arrays at the interface and transfer load to the harder phase. The stress concentration eventually leads to slip in the harder phase, overcoming the resistance from the misfit arrays at the interface. A model is developed within the framework of classical dislocation theory to estimate the strengthening from this mechanism. The model predictions are compared with experimentally measured strengths.

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Hall-Petch relations for multilayered materials

Cited by 312 publications

References 42 publications

Fretting wear analysis of TiC/VC multilayered hard coatings: experiments and modelling approaches

Fretting wear analysis of TiC/VC multilayered hard coatings: experiments and modelling approaches

Thick CrN/NbN Multilayer Coating Deposited by Cathodic Arc Technique

Dislocation Models for Strengthening in Nanostructured Metallic Multilayers

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