Influence of Cobalt Additive on Mechanical Properties and Residual Stress of Al2O3-TiC Ceramic Cutting Tool Material

Cobalt additive was added into the Al2O3-TiC composite to improve the mechanical properties. The microstructure and fracture mode of composite tool materials Al2O3-TiC and Al2O3-TiC-Co were investigated, emphasizing on the difference of thermal residual stress distribution with added cobalt. The interfacial thermal stress and the stress distribution in each phase were worked out according to thermoelasticity theory. The results demonstrated that cobalt could strengthen the interfacial bonding strength of ceramic grains and influence the residual stress distribution in Al2O3 matrix, which change the fracture mode and lead to the flexural and irregular crack propagation path.