Visco-elastic energy dissipation in a SiAlON ceramic: Quantification and implications for fatigue resistance
- Joint Research Centre of the European Commission, Petten (Netherlands). Inst. for Advanced Materials
- Leuven Univ. (Belgium). Dept. of Metallurgy and Materials Engineering
In this letter a method to estimate the visco-elastic response of monolithic ceramics to cyclic loading conditions at high temperatures is proposed. A relation is observed between the visco-elastic energy dissipation measured for two silicon nitride materials, and the structural characteristics of their respective intergranular phases. Some consequences for the fatigue resistance of the tested materials, and of non-transforming monolithic ceramics in general, are discussed. Two batches (G for glassy and C for crystalline) of SiAlON have been studied. The G-batch is obtained by pressureless sintering of silicon nitride powder with Y{sub 2}O{sub 3} (6 wt%) and 6AlN-SiO{sub 2} (5 wt%) as sintering additives. The main phase after sintering is {beta}-sialon. Upon cooling from the sintering temperature the amorphous intergranular residues of the sintering additives and of SiO{sub 2}, which is unavoidably present as a thin layer on the silicon nitride powder, crystallize partially into YAM (Y{sub 2}Al{sub 4}O{sub 9}), which is detected by both XRD and TEM.
- OSTI ID:
- 116069
- Journal Information:
- Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 9 Vol. 33; ISSN SCRMEX; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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