Crack initiation and its control in indentation into brittle materials with various indentors

摘要

This paper deals with conditions for occurrence of crack and its propagation from indents formed on a sheet of glass with a pyramid type diamond indentor or a wheel type cutter. Experiments show that, when two indents are formed at a space of about 5μm with the pyramid type indentor by loading proper weight, cracks occur at the two corners of the indents on a line through the diagonals of the adjacent indents and the cracks are connected with each other even on a condition of no crack in case of a single indent.