Superplastic Deformation of a Monolithic Silicon Nitride

Since the discovery in the early 90’ of superplasticity in a SiC/Si3N4 composite1, the superplastic behavior of covalent ceramics has become an active research area2–5. In this paper we report the superplastic behavior of a fine-grained monolithic SiAlON obtained by hot pressing of a Si3N4 powder with Al2O3 and Y2O3 as sintering aids. The superplastic forming ability of this material was studied in tension for temperature in the range 1450-1650°C and strain rates between 10−5 and 10−4/s.