J Mater Sci Technol ›› 2008, Vol. 24 ›› Issue (05): 723-728.

• Research Articles • Previous Articles     Next Articles

Effects of Nickel Distribution on the Strengthening and Toughening of Alumina Ceramics

Mohamed. M. EL-Sayed Seleman   

  1. Department of Materials and Metallurgical Eng., Faculty of Petroleum and Mining Eng., Post Code 43721, Suez, Egypt
  • Received:2007-09-27 Revised:2007-11-19 Online:2008-09-28 Published:2009-10-10
  • Contact: Mohamed. M. EL-Sayed Seleman

Abstract: 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.

Key words: Alumina-nickel composites, Nickel morphology, Interfacial bonding Fracture...