Abstract
The creep, thermal expansion, and elastic modulus properties for chemically vapour deposited SiC fibres were measured between 1000 and 1500°C. Creep strain was observed to increase logarithmically with time, monotonically with temperature, and linearly with tensile stress up to 800 MPa. The controlling activation energy was 480 ± 20 kJ mol−1. Thermal pretreatments near 1200 and 145O° C were found to significantly reduce fibre creep. These results coupled with creep recovery observations indicate that below 1400°C fibre creep is anelastic with negligible plastic component. This allowed a simple predictive method to be developed for describing fibre total deformation as a function of time, temperature, and stress. Mechanistic analysis of the property data suggests that fibre creep is the result of β-SiC grain boundary sliding, controlled by a small percentage of free silicon in the grain boundaries.
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Dicarlo, J.A. Creep of chemically vapour deposited SiC fibres. J Mater Sci 21, 217–224 (1986). https://doi.org/10.1007/BF01144723
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DOI: https://doi.org/10.1007/BF01144723