Fracture toughness evaluation of Al_2O_3/TiC+TiN tool composite by means of controiled Vickers crack growth

摘要

Due to great thennodynamic stability, high hardness and compression strength ceramics with TiC/TiN additives have better cutting properties in comparison to pure oxide ceramics [I, 2], In spite of many attractive properties of carbide reinforced composite ceramics based on AITOJ one of the primary disadvantages is their brittle nature, characterized by low fracture toughness. Fracture toughness testing of ceramics is still not standardized although some extensive affords have been recently made. A variety of testing methods exists. In this work, fracture toughness was obtained by means of indentation induced crack growth in bending [3, 4] and for comparison the conventional method based on single edge notched beam (SENB) specimens [5] was used. The tests were carried out on the Al_2O_3/3O wt% TiC+TiN and 2 wt% ZrO_2.