Effects of Precipitate Element Addition on Microstructure and Magnetic Properties in Magnetostrictive Fe83Ga17 alloy Li, Jiheng; Yuan, Chao; Zhang, Wenlan; Bao, Xiaoqian; Gao, Xuexu;
The <100> oriented alloys with various contents of NbC or B were prepared by directionally solidification method at the growth rate of . With a small amount of precipitates, the columnar grains grew with cellular mode during directional solidification process, while like-dendrite mode of grains growth was observed in the alloys with higher contents of 0.5 at% due to the dragging effect of precipitates on the boundaries. The NbC precipitates disperse both inside grains and along the boundaries of alloys with NbC addition, and the Fe2B secondary phase particles preferentially distribute along the grain boundaries in B-doped alloys. Precipitates could affect grain growth and improved the <100> orientation during directional solidification process. Small amount of precipitate element addition slightly increased the magnetostrictive strain, and a high value of 335 ppm under pre-stress of 15 MPa was achieved in the alloys with 0.1 at% NbC. Despite the fact that the effect on magnetic induction density of small amount of precipitates could be negligible, the coercivity markedly increased with addition of precipitate element for alloy due to the retarded domain motion resulted by precipitates.