High-temperature deformation of La0.2Sr0.8Fe0.8Cr0.2 O3-δ-mixed ionic-electronic conductor

Abstract

High-temperature deformation of La0.2Sr0.8Fe0.8 Cr0.2O3-δ (LSFCO) is analyzed in air environment in the stress, temperature, and grain size ranges of 10-30 (20-65) MPa, 1100-1200 °C, and 3.2-28.5 μm, respectively. The stress exponent dependence on stress is analyzed to evaluate the stress range for diffusion creep and further focus is placed on diffusion-controlled creep regime. The activation energy and inverse grain size exponent for diffusion creep are evaluated. The microstructure evolution is analyzed by scanning electron microscopy (SEM) and optical microscopy. The grain size and aspect ratio distribution evolution during creep is presented, as well as the characteristics of fracture surfaces obtained at room and elevated temperatures. The results are discussed in terms of the underlying deformation mechanisms and compared to results from creep studies on compounds with similar structures. © 2002 Elsevier Science B.V. All rights reserved.