Heterogenous microstructure and texture evolution of K-doped tungsten thick plate during hot-rolling processing

Abstract

The fabrication and processing of large bulk materials such as potassium (K)-doped tungsten pose significant technical challenges in terms of sintering and forming processes. In this study, 43 mm thick plates were prepared and hot rolled into different rolling strains. The evolution of the microstructure and texture during hot rolling was examined systematically. A heterogeneous microstructure with significant microstructural differences was observed from the edge to the core along the normal direction. Specifically, the edge was mainly composed of equiaxed fine grains, whereas the core was dominated by large pancake-shaped grains mixed with slightly elongated fine grains. This heterogeneous microstructure is attributed to the differential phenomenon, specifically dynamic recrystallization at the edge and partial dynamic recrystallization at the center. This difference arises from the strain gradient and heterogeneous distribution of K bubbles within the thick rolled plate. In addition, the dynamic recrystallization texture is predominantly influenced by the oriented nucleation effect of grains with α-fiber and γ-fiber texture components.