THE PHENOMENON OF ELASTIC DEFORMATION OF THE COATING IN THE MEASUREMENT OF TOPOCOMPOSITE HARDNESS BY INSTRUMENTED

Abstract

In this study a contact problem for an elastic-plastic layered medium is solved. From the analysis of mechanics of the contact interaction of rigid sphere with elastic rigid - plastic layered medium the analytical dependences of the effective hardness on the indentation depth of a rigid tetrahedral pyramid body are received. It is shown that at depths of indentation smaller than the so-called critical indentation depth the origin of plastic deformation occurs only in a coating material. At depths of indentation bigger than the critical indentation depth, the origin of plastic deformation occurs in a base material of a layered body and the composite hardness depends on the coating thickness, the base hardness and effective elastic characteristics of components of the layered medium and does not depend the coating hardness. In this study the opportunity to define the elastic characteristics of the coating material is proved and the calculation exercise is shown.