Ia. Chou et al., EFFECT OF ANNEALING ENVIRONMENT ON THE CRACK HEALING AND MECHANICAL-BEHAVIOR OF SILICON CARBIDE-REINFORCED ALUMINA NANOCOMPOSITES, Journal of the American Ceramic Society, 81(5), 1998, pp. 1203-1208
The crack healing and strength behavior of an alumina-silicon carbide
(Al2O3-SiC) nanocomposite (Al2O3 + 5 vol% 0.2 mu m SIC particles) has
been studied, as a function of the crack size and the annealing enviro
nment. Results show that annealing treatments can significantly increa
se the indentation strength. The annealing atmosphere has a profound i
nfluence on the extent of crack healing and the degree of strength rec
overy. Annealing in argon results in a strength increase of 50%, where
as annealing in air yields a three-fold improvement in the indentation
strength Scanning electron microscopic observation has shown that hea
ling of indentation cracks occurs in both environments, with the great
er degree of healing occurring during annealing in air. Implications o
f the findings to the strengthening mechanism in Al2O3 (SiC) nanocompo
sites will be discussed.