Insights into Microstructural and Textural Evolution during Hot Compression: An EBSD-Based Study
摘要
This study investigates the microstructure and micro-texture evolution in a two-phase Fe-Cr-Ni alloy, comprising almost equal fractions of γ-austenite (FCC) and δ-ferrite (BCC), subjected to isothermal uniaxial hot compression. Deformation was carried out at temperatures of 1150 K (877 °C) and 1250 K (977 °C), at strain rates of 0.01, 0.1, and 1 s−1, up to true strains of 0.28 and 0.69. Electron backscatter diffraction (EBSD) was utilized to characterize the deformed microstructures and to analyze the basic deformation and recrystallization mechanisms. The results revealed that δ-ferrite primarily underwent dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX), whereas γ-austenite exhibited significant discontinuous dynamic recrystallization (DDRX). In austenite, the microstructural evolution involved initial grain elongation, followed by boundary serration and substructure development, ultimately leading to the initiation of dynamic recrystallization (DRX) beyond a critical strain. Enhanced softening was noted at the elevated deformation temperature of 1250 K for both ferrite and austenite, irrespective of the strain rates applied. Additionally, increasing the strain rate resulted in a higher fraction of deformed and sub-structured regions, accompanied by a corresponding decrease in recrystallized areas. Texture analysis showed that at 1150 K, δ-ferrite formed γ-fiber and cube components, while γ-austenite displayed Brass, Goss, and rotated Goss components. At 1250 K, the texture in both phases became nearly random, indicating that significant dynamic recrystallization and grain coarsening took place at these elevated temperatures.