Effect of temperature on ferroelastic and creep behavior of LaCoO3

Abstract

The study investigates the time-dependent deformation of LaCoO3 under constant uniaxial compressive stresses at various temperatures ranging from room temperature to 880 °C. Through the acquisition of stress-strain curves at different temperatures, it has been observed that LaCoO3 exhibits non-linear ferroelastic behavior. The stiffness of LaCoO3 increases with temperature, up to 600 °C, after which it starts to decrease at higher temperatures. Furthermore, negative creep occurs at lower temperatures, whereas positive creep is observed at temperatures exceeding 600 °C. This can be attributed to transitioning from a ferroelastic creep at low temperatures to a combination of ferroelastic and high-temperature conventional creep at temperatures above 600 °C. The magnitude of both negative and positive creep is proportional to the temperature. The structural stability of LaCoO3 under creep loading at all temperatures has been assessed by comparing pre-test and post-test X-ray diffraction analyses, which showed the texture formation after testing.