Determining hardness of thin films in elastically mismatched film-on-substrate systems using nanoindentation

Han, Seung Min; Saha, Rajarshi; Nix, William D.

doi:10.1016/j.actamat.2005.11.026

Cited by 140 publications

(85 citation statements)

References 6 publications

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“…The discrete dislocation results indicate that the indentation pressure increases with increasing indentation depth for d=h40:05 and 0.1 for the o ¼ 5 and 10 wedges, respectively. While the calculated indentation depths at which an increase in indentation pressure occurs are comparable to those seen experimentally by Han et al (2006) and Saha et al (2001), a quantitative comparison is not appropriate because the situation modeled here differs from that in the experiments in a variety of ways including differences in the indenter geometry and in the ARTICLE IN PRESS elastic mismatch between the film and the substrate. Saha et al (2001) have shown that appropriately calibrated strain gradient plasticity theories are capable of predicting this initial decrease and then increase in hardness with increasing indentation depth for the thin films, while conventional plasticity calculations significantly over-predict the indentation depths at which the plastic zone interacts with the substrate.…”

Section: Article In Pressmentioning

confidence: 80%

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: Article In Pressmentioning

confidence: 80%

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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“…Other researchers have shown that the elastic mismatch between the film and the substrate materials is one of the main reasons that causes incorrect hardness values [9]. We propose to reduce the elastic modulus mismatch effect on the measured thin film hardness.…”

Section: Resultsmentioning

confidence: 99%

“…Joslin and Oliver [8] suggested that the ratio of the indentation load and the square of the unloading stiffness, P/S 2 , is a material characteristic. For bulk materials, the value of P/S 2 does not change much with the indentation depth [9]. Former studies have shown that the Joslin-Oliver method is only good for homogeneous materials with similar modulus [9], thus many researchers utilized FEM to model the substrate effect and correct the measured reduced modulus.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Evaporated Gold Films. Hard Substrate Effect Correction

Pang

Chen

et al. 2008

MRS Proc.

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Nanoindentation tests using the Berkovich indenter tip were performed on 50 and 200 nm thick polycrystalline gold films deposited on hard substrates. Gold film hardness increased with the indentation depth due to the influence of the substrate. A procedure based on the Joslin-Oliver method was introduced to correct for the substrate effect. The method utilizes the fact that the measured elastic modulus did not change significantly with the indentation depth for the two films tested, which allowed reducing the contact area variation used in the hardness calculation.

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“…A number of studies with several different approaches to modeling the substrate effect have been reported [7][8][9][10][11][12][13]. King used numerical techniques to model the elastic indentation of a layered half space with flat-ended punches of various cross-sections [8].…”

Section: Introductionmentioning

confidence: 99%

Determining the elastic modulus and hardness of an ultra-thin film on a substrate using nanoindentation

Vlassak

2009

J. Mater. Res.

160

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The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters. Abstract -A data analysis procedure has been developed to estimate the contact area in an elasto-plastic indentation of a thin film bonded to a substrate. The procedure can be used to derive the elastic modulus and hardness of the film from the indentation load, displacement, and contact stiffness data at indentation depths that are a significant fraction of the film thickness. The analysis is based on Yu's elastic solution for the contact of a rigid conical punch on a layered half-space and uses an approach similar to the Oliver-Pharr method for bulk materials. The methodology is demonstrated for both compliant films on stiff substrates and the reverse combination and shows improved accuracy over previous methods.

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Determining hardness of thin films in elastically mismatched film-on-substrate systems using nanoindentation

Cited by 140 publications

References 6 publications

Discrete dislocation plasticity analysis of the wedge indentation of films

Discrete dislocation plasticity analysis of the wedge indentation of films

Mechanical Properties of Evaporated Gold Films. Hard Substrate Effect Correction

Determining the elastic modulus and hardness of an ultra-thin film on a substrate using nanoindentation

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