High-temperature deformation behavior in SrTiO3 ceramics |
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| Affiliation: | 1. Argonne National Laboratory, Argonne, IL 60439, USA;2. Departmento de Fisica de la Materia Condensada, Universidad de Sevilla, Sevilla 41080, Spain;1. Stuttgart Center for Electron Microscopy, Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany;2. Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, 41092 Sevilla, Spain;1. Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany;2. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, 52425 Jülich, Germany;3. Laboratory of Solid State Ionics, College of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China |
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| Abstract: | The high-temperature deformation behavior of a polycrystalline strontium titanate (SrTiO3) ceramic (6 μm 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 × 10?6 to 5 × 10?5 s?1. Steady-state flow stresses were 0.05–30 MPa and increased with increasing strain rates. Stress exponents of ≈1, at temperatures >1200 °C, indicated a viscous diffusion-controlled deformation with an activation energy of ≈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° at a strain of 4%. |
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