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Title: Creep of polycrystalline SrCo{sub 0.8}Fe{sub 0.2}O{sub 3{minus}{delta}}

Abstract

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.

Authors:
; ;
Publication Date:
Research Org.:
Univ. of Houston, TX (US)
OSTI Identifier:
20075942
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 48; Journal Issue: 8; Other Information: PBD: 11 May 2000; Journal ID: ISSN 1359-6454
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MICROSTRUCTURE; CREEP; STRONTIUM OXIDES; COBALT OXIDES; IRON OXIDES; POLYCRYSTALS; TEMPERATURE RANGE 1000-4000 K; STRESSES; STRAIN RATE; DIFFUSION

Citation Formats

Majkic, G., Wheeler, L., and Salama, K. Creep of polycrystalline SrCo{sub 0.8}Fe{sub 0.2}O{sub 3{minus}{delta}}. United States: N. p., 2000. Web. doi:10.1016/S1359-6454(99)00472-3.
Majkic, G., Wheeler, L., & Salama, K. Creep of polycrystalline SrCo{sub 0.8}Fe{sub 0.2}O{sub 3{minus}{delta}}. United States. doi:10.1016/S1359-6454(99)00472-3.
Majkic, G., Wheeler, L., and Salama, K. Thu . "Creep of polycrystalline SrCo{sub 0.8}Fe{sub 0.2}O{sub 3{minus}{delta}}". United States. doi:10.1016/S1359-6454(99)00472-3.
@article{osti_20075942,
title = {Creep of polycrystalline SrCo{sub 0.8}Fe{sub 0.2}O{sub 3{minus}{delta}}},
author = {Majkic, G. and Wheeler, L. and Salama, K.},
abstractNote = {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.},
doi = {10.1016/S1359-6454(99)00472-3},
journal = {Acta Materialia},
issn = {1359-6454},
number = 8,
volume = 48,
place = {United States},
year = {2000},
month = {5}
}