TiN/Al2O3 composites and graded laminates thereof consolidated by spark plasma sintering

A rapid consolidation process named Spark Plasma Sintering (SPS) has been applied to compact duplex TiN/Al2O3 composites and graded laminates thereof. Fully or nearly fully compacted samples were prepared at 1500 degreesC with a holding time of 3 min under a pressure of 75 MPa. The unusually high grain-growth rate of Al2O3 occurring in monolithic Al2O3 at this sintering temperature is prevented by the addition of TiN particles. Crack-free graded laminates with distinct interfaces between layers were prepared by loading samples inside the die, both symmetrically and asymmetrically. The observed mechanical properties, e.g. hardness and fracture toughness, are related to the microstructural features of the compacted samples. (C) 2002 Elsevier Science Ltd. All rights reserved.