High-temperature deformation behavior in SrTiO3 ceramics

• Published in: Journal of the European Ceramic Society Vol. 27; no. 11; pp. 3377 - 3384
• Main Authors: SINGH, D, LORENZO-MARTIN, M, CHEN, G, GUTIERREZ-MORA, F, ROUTBORT, J. L
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Oxford Elsevier 2007
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; Structural ceramics; Technical ceramics; Grain boundaries; Scanning electron microscopy; Deformation; Polycrystal; Mechanical properties; SrTiO3; Plastic deformation; High temperature; Experimental study; Oxide ceramics; Structural ceramic; Grain boundary; Strontium titanates
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2007.02.186

The high-temperature deformation behaviour of a polycrystalline SrTiO3 ceramic (6 micron grain size) was investigated at 1200-1345 C in an argon atmosphere. Compressive deformation tests were conducted at strain rates ranging from 5 x 10 exp(-6) to 5 x 10 exp(-5)/s. Steady-state flow stresses were 0.05-30 MPa and increased with increasing strain rates. Stress exponents of about 1, at temperatures > 1200 C, indicated a viscous diffusion-controlled deformation with an activation energy of about 628 plus or minus 24 kJ/mol. Comparison of activation energy with literature data suggested 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. EBSD 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%. 34 refs.