The Effect of Rare Earth Y on the Inhibitor Precipitation Behavior of Strip-Cast Grain-Oriented Silicon Steel

0.3 mm-thick grain-oriented silicon steel sheets with varying Y contents are produced via twin-roll strip-casting and two-stage cold rolling process. This study primarily investigates the evolution of microstructure, texture, and precipitation along the processing. Specifically, the effect of rare earth Y on second-phase particle precipitation in ultralow carbon grain-oriented silicon steel is examined. Results indicate that higher Y content will consume beneficial inhibitor elements such as S and N, leading to the formation of coarse rare earth inclusions (approximate to 10 mu m) in the cast strip. This significantly diminishes inhibition ability and magnetic induction (B8 = 1.58 T approximate to 1.71 T). On the contrary, the addition of trace Y can accelerate the precipitation of inhibitors. During the intermediate annealing stage, steel with trace Y exhibits a significant enhancement in precipitate distribution density (from 2.8 mu m-2 to 13.6 mu m-2), and the final magnetic induction B8 increases from 1.86 T to 1.91 T compared to steel without Y. In addition, the results of first-principle calculations based on density functional theory reveal that the doped Y atom prefers to segregate at the Al-N interface, and the interface energy reduces from 1.871 J m-2 to 1.024 J m-2, thereby promoting the precipitation of AlN. The addition of trace rare earth Y to the strip-cast grain-oriented silicon steel can promote the rapid precipitation of AlN inhibitors. The doped Y atoms tend to segregate at the Al-N interface and reduce the precipitated interface energy.image (c) 2024 WILEY-VCH GmbH