FIELD: measuring tools.
SUBSTANCE: determining residual stresses in a thin hard stressed coating deposited on a non-rigid substrate. The method consists in the fact that the coated product, in which residual stresses are present, is subjected to microindentation to obtain a penetration diagram, which contains two indentation cycles. The first cycle provides interfacial separation of the coating in a certain area without destroying the continuity of the coating. The second loading cycle is carried out in the same indentation as in the first indentation cycle, but with loading providing elastic deformation of the coating under the indenter. Based on the results of the analysis of the repeated loading and unloading curves, a loading curve is constructed for a coated product without the presence of residual stresses in it. Analytical processing of these loading curves for a coating with residual stresses and an unstressed coating makes it possible to determine the radius of the interfacial crack and the deflection of the bulge of the coating. Taking into account the known initial data on the coating material and thickness, the value of residual stresses in the coating is calculated by mathematical dependence.
EFFECT: simplification of the procedure for determining residual stresses by taking into account the deformation of the substrate material and the presence of the effect of interfacial lamination.
8 cl, 4 dwg
