Dependence of microcrack densities in thermally sprayed coatings on deformation

摘要

Young's moduli of thermally sprayed coatings, measured at small deformations, are known to be much smaller than those of well sintered materials, due to a high density of microcracks. Moreover, at higher deformations the behaviour of coatings is strongly nonlinear, which may be attributed to changes in microcrack densities with deformation. In this paper, the dependence of the microcrack densities on compressive and tensile deformation is predicted on the basis of two known dependences: theoretically predicted dependence of Young's modulus on microcrack density and the nonlinear stress-strain relation.