High temperature creep of polycrystalline mullite
High temperature compressive creep of two different mullite polycrystals, at temperatures ranging between 1400 and 1500 C, has been studied in order to determine the mechanism controlling the deformation. Microstructural characterization of the as received materials revealed grain size and the amount and composition of glassy phases at the grain boundaries, with one mullite containing some silica rich glassy phase, and the other virtually free of it. Values for the creep activation energy (Q) of 970 kJ/mol for the mullite with some glassy phase, and 770 kJ/mol for the very pure mullite, have been obtained. Grain boundary sliding (GBS) is considered to be the main mechanism for creep; the difference in the values of Q would reflect the control of GBS by a different process in each material; viscous flow or diffusion controlled accompanied by cavitation.
| Main Authors: | , |
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| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Trans Tech Publications
1997
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| Online Access: | http://hdl.handle.net/10261/223254 |
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