Microstructure and texture evolution in austenitic stainless steel during low strain rate deformation at elevated temperature

Abstract

Microstructure and texture development in an austenitic stainless steel at high temperatures and low strain rate were studied through laboratory scale compression and rolling experiments. The uniaxial compression tests were performed under constant temperature with sample temperatures of 900 °C, 1000 °C and 1100 °C whereas, the rolling experiments were performed at the same initial sample temperatures but in a transient condition. The average strain rate was 1 s⁻¹ and 1.23 s⁻¹, during the compression and rolling experiments, respectively. After deformation the microstructure and texture developed in the samples were examined through the electron back scattered diffraction technique. For compression test, deformation at 900 °C produces mostly deformed grains whereas, at 1000 °C and 1100 °C only recrystallized grains were observed. In contrast, rolling produces partially recrystallized microstructures at all the three temperatures. Finite element (FE) modeling was used to calculate the variation of the state variables like temperature, strain and strain rate and the differences in microstructure for the two processes were analyzed in the light of FE simulation results. In texture, tube orientation like α fiber was developed by the compression at 900 °C whereas, at 1000 °C and 1100 °C random texture with cube as the significant texture component, was observed. Similarly in rolling, α, β and τ fibers with different intensities were developed at the center and random texture was observed near the surface of the samples.