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Three types of composite materials were designed and fabricated by hot pressing powder blends of alumina with 20 vol.pct nickel particles.The composites differ in the shape,size and distribution of the nickel particles. Composite microstructures are described and measurements of density,hardness,flexure strength,and fracture toughness are reported.The results showed that the fracture strength of the composite with dispersed nickel particles is higher than the other two composites(network microstructure and mixed microstructure)and the alumina matrix.For all the composites studied,tougher materials than the monolithic alumina were produced. The fracture toughness of the composite with a network microstructure is much higher than that of the other composites.The toughening mechanisms were described based on the observation of the fracture surfaces and the crack-particle interactions.Moreover,the parameters for microstructural tailoring of these materials have been deduced.The toughening of the produced composites was explained in light of the interfacial bond strength.
Three types of composite materials were designed and fabricated by hot pressing powder blends of alumina with 20 vol. Pct nickel particles. Composites differ in the shape, size and distribution of the nickel particles. Composite microstructures are described and measurements of density, hardness, flexure strength, and fracture toughness are reported. the results showed that the fracture strength of the composite with dispersed nickel particles is higher than the other two composites (network microstructure and mixed microstructure) and the alumina matrix. For all the composites studied, tougher materials than the monolithic alumina were produced. The fracture toughness of the composite with a network microstructure is much higher than that of the other composites. toughening mechanisms were described based on the observation of the fracture surfaces and the crack-particle interactions. More over, the parameters for microstructural tailoring of these materials have been deduced.The toughening of the produced composites was explained in light of the interfacial bond strength.