Cracking in Brittle Coatings during Nanoindentation

Abstract:

The FIB/SEM investigations of the microstructure changes in the hard brittle W-C based coating deposited on softer steel substrate after nanoindentation tests revealed that a set of approximately equidistant circular cracks forms in the coating in a sink-in zone around the indent and single cracks appear under the indenter tip. Finite element modeling (FEM) indicated development and concentration of the highest principal tensile stresses in the sink-in zone and in the zone below the indenter, which are considered to be the reason for the experimentally observed cracking. The distance from the indenter tip to the first circular crack combined with the calibration curve obtained from the FEM of the location of tensile stress maxima in sink-in zone can be used as a simple method for the determination of the strength of the studied coatings.

• Periodical: Key Engineering Materials (Volume 662)
• Pages: 103-106
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.662.103
• Online since: September 2015
• Authors: František Lofaj*, Dušan Németh, Rudolf Podoba, Michal Novák
• Keywords: Coating Strength, Finite Element Modeling, Microcracks, Nanoindentation, W-C Coating

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