Analysis of hard coatings on a substrate containing inhomogeneities

We investigate the effect stiff inhomogeneities in the substrate beneath a hard coating have on the elastic field. The solution of multiple interacting three-dimensional inhomogeneities in a half-space is utilized by modeling a coating layer as an inhomogeneity of finite size. The study shows that stiff inhomogeneities in the substrate do not worsen the cracking and debonding of hard coatings, but are still detrimental to the yielding behavior of the substrate even though it is under the protection of a hard coating.