J. Hefter et al., MICROSTRUCTURAL CHARACTERIZATION OF STRUCTURAL CERAMICS USING IMAGE-PROCESSING AND ANALYSIS, Journal of the American Ceramic Society, 76(6), 1993, pp. 1551-1557
Digital imaging and analysis methods are applied to the quantitative s
tudy of microstructural changes which occur during hot-pressing of ytt
ria-doped silicon nitride. Effects of processing changes upon the grai
n growth and microstructural anisotropy are described. Relationships b
etween grain cross-sectional area and mechanical properties are establ
ished. It was found that, over the range of processing conditions used
, increases in grain size correlated strongly with an increase in frac
ture toughness. The grain size distribution broadened significantly wi
th hot-press time, resulting in reduced flexural strength. Although no
significant change in the mean grain shape factor was observed, the v
ariance in shape factor decreased as the hot-press time was extended.