Effect of Chemical Composition of Intergranular Glass on Superplastic Deformation of β-Silicon Nitride
In this study, the effect of composition of intergranular glass on superplastic compressive deformation of -Si3N4 has been studied by compression tests. Oxide additives were used to form Y2O3-Al2O3-SiO2 melt and, with increasing temperatures, an oxynitride melt (Y-Al-Si-O-N) by dissolving Si3N4. The relation between flow stress and glass composition qualitatively corresponded to the effect of chemical composition on viscosity of Y2O3-Al2O3-SiO2 glass. However, the rate of increase of the flow stress was not proportional to the viscosity of Y2O3-Al2O3-SiO2 glass, probably because the composition of intergranular glass phase had changed by dissolving Si3N4 and by crystallization of Si2N2O.
T. Ohji, T. Sekino and K. Niihara
E. Narimatsu et al., "Effect of Chemical Composition of Intergranular Glass on Superplastic Deformation of β-Silicon Nitride", Key Engineering Materials, Vols. 317-318, pp. 399-402, 2006