The thermal shock behaviour of ductile particle toughened alumina composites

Over recent years, it has been established that rite incorporation of metal lic particles into a ceramic matrix can lead to enhanced fracture propertie s. Relatively few attempts, however, have been made to establish whether or Mot the improved fracture toughness typically observed in such composite s ystems can offer improved performance in demanding environments. The curren t study, is concerned with the thermal shock behaviour of a ceramic matrix composite consisting of an alumina matrix containing 20 vol% of discrete ir on particles. The composite material has been produced by both hot pressing and conventional sintering techniques. The hot pressed composite shows a g reater resistance to thermal shock than the monolithic matrix, both in term s of the critical temperature differential and retained strength, whereas t he sintered material has been found to behave as a typical low strength ref ractory ceramic. The calculation of thermal shock resistance parameters for the composites and the monolith has indicated possible explanations for th e differences in thermal shock behaviour. (C) 1999 Elsevier Science Limited . All rights reserved.