Determination of the Specific Energy of Elastoplastic Strain Required for Crack Formation in Hardening Coatings upon Indentation
Current methods of assessing crack resistance of strengthened surfaces using pyramidal indenter are intended only for the case of radial crack formation around the indenter. However, for certain types of hardening coatings, e.g., titanium nitride based coatings, indentation leads to formation of ring rather than radial cracks around the indenter. For this case of crack formation, we propose to use kinetic diagram of indentation to determine the specific energy of elastoplastic deformation which provides formation of the first visible crack. This energy can be used to compare the ability of coatings to withstand any kind of crack formation.