Microstructures and Toughening Mechanisms of Alumina-Matrix Composites

Various toughening methods, such as transformation toughening, transformation-whiskerreinforcement and transformation-particle reinforcement were used toimprove the mechanical properties of alumina.The fracture behaviors and toughening mechanisms of the composites werc studied by measuringmechanical properties, analyzing microstructures and comparing fracture morphologies. The mechanical propertiesof testing materials arc closely related with the morphologies of fracturc surfaces. The two tougheningmcchanisms in joint toughening composites will affect with each other, and produce an effect ofcooperative toughening on certain conditions. The dislocations were observed in matrix of meterials undergoingproperty test. The tearing ridges, which are created generally in ductile fracture, were also observed onfracture surface in ZTA material.