Gradient Recrystallization Behavior of a Moderate Warm-Rolled Non-Oriented Fe-6.5wt%Si Alloy

In Fe-Si alloy systems, the Fe-6.5wt%Si alloy shows low iron core losses and near-zero magnetostriction, thus having great potential for high-frequency applications. In this study, an Fe-6.5wt%Si alloy hot band was subjected to a moderate warm rolling with a thickness reduction of 40%, and then annealed at different temperatures. The recrystallization behavior was investigated using the EBSD technique. After the moderate warm rolling, the initial gradient structure of the hot band is inherited, leading to gradient recrystallization behaviors during the further annealing process. The sheet surface first densely nucleates and forms strong //ND and {221} textures. However, the //ND and {221} grains have fewer high-mobility and high-energy (20–45°) boundaries than the other oriented matrix grains, leading to insufficient growth advantages. In the center region, the recrystallization is slow, but the nuclei usually have larger sizes. The inheritance of the //ND (θ-fiber) texture from the initial hot band appears. Some θ-fiber grains, which have easy-magnetized axes lying in the sheet plane, preferentially nucleate in the strong α-fiber textured matrices and form a strong θ-fiber recrystallization texture in the center region.