Journal of the European Ceramic Society vol:15 issue:4 pages:297-305
Toughening of an X-sialon matrix with up to 53 volume percent Al2O3 platelets was investigated. The effect of platelet content on both matrix phase composition and mechanical properties of the composites was evaluated. The extent of cracks introduced by Vickers hardness indentations showed a reduced length with increasing platelet content, indicating an increase in fracture toughness. The toughness has been shown to increase from 1.77 MPa . m(1/2) for pure X-sialon up to 4.16 MPa . m(1/2) for the composite containing 28 volume percent platelets. For higher platelet additions, toughness increases further but the composition of the matrix shifts to beta'-sialon. The E-modulus of the composites increases with the amount of platelets. The improvement in fracture toughness was attributed to debonding, crack bridging and crack deflection.