Effects of the Irregular Interfacial Geometry and Elastic Properties of Ceramic Compounds on the Strength of Steel with a Composite Coating

摘要

This study aims to clarify the effects of the elastic property difference in a composite coating as well as of the serrated coating-substrate interface on the mechanical properties of austenitic steel coated with Si-based ceramic. Effective mechanical properties of the coated steel are calculated for a range of different hypothetical and real filler materials. The microstructure of the particle-filled coating corresponds to that observed experimentally. Composite, where inclusions are characterized by higher Young's modulus Ef than the coating matrix, possesses higher strength as compared to a composite with fillers characterized by lower Young's modulus. Filler material characterized by Ef= 1.5E_m, with E_m denoting the Young's modulus of the coating matrix, gives the best strength for the "particle-filled ceramic coating - steel substrate" composite. Tensile stresses are observed to concentrate in various places in the course of loading: in the steel substrate near local minima of the coating-substrate interface in the initial loading stage, and in the ceramic coating near local maxima (peaks) of the interface in the stage of developed plastic flow.