Evolution of microstructures and microtextures during hot deformation of solid solution-strengthened superalloys

Abstract

Using Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM), the evolution of microstructures and microtextures of the ERNiCrMo-3 alloy under various deformation conditions were investigated and the slip characteristics of dominant grains with different orientations were analyzed. The results indicate that both the overall structures, as well as the recrystallized structures without significant grain growth, form a <110> fiber texture. Additionally, a higher proportion of the original structure corresponds to a higher maximum measured pole density (PMAX). In contrast, the recrystallized structures with pronounced grain growth tend to rotate to <001> axis due to preferential grain growth. The micro textures are primarily characterized by $\alpha$-fiber textures composed of Brass, Goss, and P components under different deformation conditions. The Brass component is most prominent at the initial stage of dynamic recrystallization (DRX), while the Goss texture increases significantly under conditions favorable for DRX. As DRX progresses to completion, all texture components weakened. Grains with dominant orientations of Brass, Goss, or P have at least two slip systems activated, leading to the formation of dislocation wall substructures parallel to the slip planes within the grains. Orientation-dependent slip results in specific directions being softer or harder within the grains. Under the influence of slip, the ERNiCrMo-3 alloy readily forms a Brass texture. Due to differences in structural energy and Schmid factors between the Brass texture and other textures, the Brass component occupies a larger proportion under various conditions.