Creep of polycrystalline SrCo{sub 0.8}Fe{sub 0.2}O{sub 3{minus}{delta}}
In this study, a series of compressive creep tests on rectangular specimens of SrCo{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} of grain sizes in the range of 2.4--6.8 {micro}m was performed to air, covering a temperature range of 850--975 C and a stress range of 2--80 MPa. The stress exponent has been found to be close to unity in the 10--20 MPa stress range. The apparent activation energy assumes two different values, 471 kJ mole below 925 C and 275 kJ/mole above 925 C. The microstructural observations of crept samples revealed equiaxed grains and negligible grain growth indicating a diffusion-accommodated grain switching mechanism. The logarithmic plot of strain rate vs inverse grain size has been found to be non-linear. A possible explanation for this behavior is discussed through the incorporation of a threshold stress. The possibility of estimating the lattice and grain-boundary diffusion coefficients from the data is discussed.
- Research Organization:
- Univ. of Houston, TX (US)
- OSTI ID:
- 20075942
- Journal Information:
- Acta Materialia, Vol. 48, Issue 8; Other Information: PBD: 11 May 2000; ISSN 1359-6454
- Country of Publication:
- United States
- Language:
- English
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