Main Regularities of Elastic-Plastic Deformation and Brittle Failure in Micro Volumes of Abrasive Materials under Micro Pressure

Abstract There the results of the investigations of surface strength and fracture toughness of abrasive and other highly rigid materials using the method of micro pressure that provides high degree of localization of the application of an external force action, are presented. The basic regularities of elastic-plastic deformation and brittle failure in the process of microindentation were determined for all the investigated materials. Based on the studies we also identified the power and energy conditions of elastic-plastic deformation and brittle failure in the process of microindentation of highly rigid and brittle materials. It was found, that in the 1 st stage of the deterioration process the specific work of fracture and the stress intensity factor are directly proportional to the size of the stress concentrator, i.e. the imprint diagonal. Therefore the stress intensity factor, that is widely used in mechanics and micromechanics of materials, can be valid only when it is defined in terms of sustainable growth of cracks in the 2 nd stage of brittle fracture of the investigated material. According to test results we obtained the main characteristics of strength and fracture toughness of a number of abrasive materials used in industry and research organizations.