Microstructure and fracture behavior of hot-pressed TiC Si₃N₄ composites

Silicon nitride containing various compositions of TiC were hot-pressed at 1800°C for 1 h in a nitrogen atmosphere. The grain growth was inhibited and the aspect ratio was slightly decreased with the addition of TiC. Cracks were often observed cleavaging along preferred orientations inside TiC with large deflected angles. Typical secondary brittle fracture patterns were observed inside TiC with fracture initiated near the TiC surface. Fracture toughness was enhanced by 30% with the addition of 20% vol TiC.