Superplastic Sinter-Forging of Fine-Grained Si3N4-Si2N2O Composite at Low Temperature
The Si3N4- Si2N2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering (LPS) method. XRD analysis shows sintered body consists of β-Si3N4 and Si2N2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is only 1550°C. Rod-shaped grains aligned along the perpendicular direction of pressure and the mechanical properties increase about 10% after the materials were forged.
J. T. Luo and Q. Zhang, "Superplastic Sinter-Forging of Fine-Grained Si3N4-Si2N2O Composite at Low Temperature", Materials Science Forum, Vols. 551-552, pp. 487-490, 2007