Experimental Determination of Brittle Fracturing Appearance During Static Indentation of Materials Based on Stone

摘要

During micro cutting process, the presence of both ductile and brittle mode is observed. The appearance of one or the other, or the value of critical penetration depth, when transition is happening, depends on the material itself, cutting condition, tool geometry and its motion as well. Widely used method for determining critical penetration depth is static indentation with diamond indenter. This paper presents experimental determination of critical penetration depth for material based on stone. Static indentation is used with Vickers indenter. It is shown that, with increase of indentation load, first phase lacks the appearance of micro cracks. After exceeding the threshold force (penetration depth), micro cracks appear, which is then followed by severe destruction of the material. Due to its material properties, penetration depth is not constant. It varies from grain to grain.