A universal relation for edge chipping from sharp contacts in brittle materials: A simple means of toughness evaluation

An analysis of chipping fracture in brittle solids is presented. Cracks are introduced into the edges of selected materials, including soda-lime glass and fine-grain ceramics, using a Vickers indenter in monotonic loading. The ensuing chip morphology is examined and shown to exhibit a certain geometrical similarity, independent of material properties. A simple universal relation is derived for the critical chipping load in terms of indent location and material toughness. It is suggested that the method could be used as a simple and quick means for evaluating toughness values for glasses and fine-grain brittle materials.