Elasto-plastic characterisation of CVD diamond based on nano-hardness data and finite element simulations
Elasto-plastic characterisation of CVD diamond based on nano-hardness data and finite element simulations
The development of chemical vapour deposition (CVD) technologies has allowed the deposition of polycrystalline diamond on an industrial scale. Despite the enormous potential of CVD diamond, reliable data on its mechanical properties are relatively limited. Measurement of these properties is difficult because of the extreme hardness of diamond, and proper interpretation of test results is complicated by issues of film quality and morphology. A large number of authors have investigated the mechanical properties of CVD diamond coatings, i.e. elastic modulus, hardness and fracture toughness, by using nano and micro hardness indentation techniques. A comprehensive literature review on the current activities in characterisation of CVD diamond is reported in this thesis.
The nano-indentation technique has been used to determine the elastic modulus and the hardness in thin film coatings (supplied by De Beers, Ascot (now Element Six) with different coating thickness (10 and 100 ?m) using a Berkovich indenter. Results in terms of loading and unloading curves has moreover been used to best fit a predictive numerical model of indentation process, also developed as part of the work reported here. Load-displacement experimental data were compared and found in good agreement with those predicted by FE analysis. Spherical indenters with different radius are also considered in FEM simulations of nano-indentations. The stress field produced around the indenter tip and in the CVD diamond film is determined. Hertz theory has been used to validate the numerical model in the elastic range. The stress field obtained by FEM is compared with those predicted by Hertz theory and found in good agreement with an average error less than 2%. The assessed numerical model for elastic solution is developed further to account for elasto-plastic deformation, thus predicting the residual depth observed during indentation tests.
De Fazio, Luca
644988c6-1692-412c-9e7a-adefc047f88b
April 2006
De Fazio, Luca
644988c6-1692-412c-9e7a-adefc047f88b
Wood, Robert
d9523d31-41a8-459a-8831-70e29ffe8a73
De Fazio, Luca
(2006)
Elasto-plastic characterisation of CVD diamond based on nano-hardness data and finite element simulations.
University of Southampton, School of Engineering Sciences, Masters Thesis, 72pp.
Record type:
Thesis
(Masters)
Abstract
The development of chemical vapour deposition (CVD) technologies has allowed the deposition of polycrystalline diamond on an industrial scale. Despite the enormous potential of CVD diamond, reliable data on its mechanical properties are relatively limited. Measurement of these properties is difficult because of the extreme hardness of diamond, and proper interpretation of test results is complicated by issues of film quality and morphology. A large number of authors have investigated the mechanical properties of CVD diamond coatings, i.e. elastic modulus, hardness and fracture toughness, by using nano and micro hardness indentation techniques. A comprehensive literature review on the current activities in characterisation of CVD diamond is reported in this thesis.
The nano-indentation technique has been used to determine the elastic modulus and the hardness in thin film coatings (supplied by De Beers, Ascot (now Element Six) with different coating thickness (10 and 100 ?m) using a Berkovich indenter. Results in terms of loading and unloading curves has moreover been used to best fit a predictive numerical model of indentation process, also developed as part of the work reported here. Load-displacement experimental data were compared and found in good agreement with those predicted by FE analysis. Spherical indenters with different radius are also considered in FEM simulations of nano-indentations. The stress field produced around the indenter tip and in the CVD diamond film is determined. Hertz theory has been used to validate the numerical model in the elastic range. The stress field obtained by FEM is compared with those predicted by Hertz theory and found in good agreement with an average error less than 2%. The assessed numerical model for elastic solution is developed further to account for elasto-plastic deformation, thus predicting the residual depth observed during indentation tests.
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Published date: April 2006
Organisations:
University of Southampton, Engineering Mats & Surface Engineerg Gp
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Local EPrints ID: 64791
URI: http://eprints.soton.ac.uk/id/eprint/64791
PURE UUID: bdc7e88c-c991-4bf0-8090-62bdb82cf9fa
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Date deposited: 24 Mar 2009
Last modified: 16 Mar 2024 02:46
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Author:
Luca De Fazio
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