An improved Vickers indentation fracture toughness model to assess the quality of thermally sprayed coatings

This study presents an improved approach to the quality assessment of thermally sprayed coatings. Measurements were carried out on five different coatings. Since it is the overall extent of surface cracking during Vickers indentation that is indicative of the volumetric damage, the surface crack length was measured, including the radial cracks, edge cracks, and other cracks around the indentation. It is concluded that the proposed model provides a way forward for determining the fracture toughness (K1c) of brittle materials where no radial cracks are developed. An elastic–plastic finite element simulation of the Vickers indentation test was conducted to locate the stress fields.