Determination of work of initiation and propagation of cracks during instrumental indentation of brittle materials and hardening coatings

Known methods for determining the critical stress intensity factor K1c of surface layers of materials by indentation of a pyramid for the case of the formation of radial cracks emanating from the tops of the indentation have been considered. It is noted that the existing methods for assessing the crack resistance of materials by indentation do not allow determining the work of crack initiation. A technique for determining the specific work of crack initiation and the specific work of their propagation along the critical points of the pyramid indentation diagram during instrumental indentation is proposed. A correlation was established between the energy criterion of crack resistance G1с and the specific work of crack propagation ωр, determined from the indentation diagram, for brittle materials and hardening coatings. This makes it possible to develop a method for the rapid assessment of the critical stress intensity factor K1c from the indentation diagram during instrumental indentation without measuring the geometric parameters of the resulting cracks and regardless of their type.