Nanoindentation and AFM Studies on Tungsten Carbide Crystals in WC-Co Hardmetal

Tamás Csanádi; Marek Bľanda; Annamária Duszová; Pavol Hvizdoš; Ján Dusza

doi:10.4028/www.scientific.net/KEM.606.107

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HomeKey Engineering MaterialsKey Engineering Materials Vol. 606Nanoindentation and AFM Studies on Tungsten...

Nanoindentation and AFM Studies on Tungsten Carbide Crystals in WC-Co Hardmetal

Abstract:

The room temperature elastic and plastic properties of the WC grains of WC-9%Co hardmetal were investigated by nanoindentation and atomic force microscope (AFM). Two easily distinguishable crystallographic planes (using EBSD analyses) were investigated, namely the basal and prismatic planes, on which nanoindentation tests were performed with different applied loads from 1 mN to 50 mN to determine the hardness and reduced-modulus, respectively. The results deriving from nanoindentation show significantly higher indentation hardness on basal planes (H_IT=28.9±0.1 GPa) than on prismatic ones (H_IT=21.9±0.1 GPa) over 10 mN load. For loads below that the results were inconsistent. The corresponding indents were checked by AFM and correct values of hardness were found. The discrepancies indicate the inaccuracy of the built-in evaluation procedure (Oliver-Pharr method) in this low load, or more precisely in the low indentation depth range. It is pointed out that below 50 nm contact depth the applied built-in contact area-contact depth function is not appropriate and a new correct contact area-contact depth function is proposed, thus the resulting recalculated hardness values are in good agreement with the AFM measurements.

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Periodical:

Key Engineering Materials (Volume 606)

Pages:

107-110

DOI:

https://doi.org/10.4028/www.scientific.net/KEM.606.107

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Online since:

March 2014

Authors:

Tamás Csanádi*, Marek Bľanda, Annamária Duszová, Pavol Hvizdoš, Ján Dusza

Keywords:

AFM, Basal Plane, Hardmetal, Nanohardness, Prismatic Plane

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