High-temperature deformation behavior in Sr TiO{sub 3} ceramics.
The high-temperature deformation behavior of a polycrystalline strontium titanate (SrTiO{sub 3}) ceramic (6 {micro}m grain size) was investigated at temperatures of 1200-1345 C in an argon atmosphere. Compressive deformation tests were conducted at strain rates ranging from 5 x 10{sup -6} to 5 x 10{sup -5} s{sup -1}. Steady-state flow stresses were 0.05-30 MPa and increased with increasing strain rates. Stress exponents of {approx}1, at temperatures >1200 C, indicated a viscous diffusion-controlled deformation with an activation energy of {approx}628 {+-} 24 kJ/mol. Comparison of activation energy with literature data suggests diffusion of cations as the rate-controlling mechanism. Absence of cavitation and grain-shape changes were consistent with grain-boundary sliding as the principal deformation mechanism. The electron back-scattered diffraction (EBSD) technique was used to determine the grain orientation as a function of applied strain. The results indicate that some of the grains rotate with cumulative rotation as large as 7 degrees at a strain of 4%.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- EE
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 914805
- Report Number(s):
- ANL/NE/CP-118953; TRN: US200812%%75
- Journal Information:
- J. European Ceram. Soc., Vol. 27, Issue 11 ; 2007; Conference: Mechanical Properties in Advanced Materials: Recent Insights; Jun 7-11, 2006; Fuenteheridos, Spain
- Country of Publication:
- United States
- Language:
- ENGLISH
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