Effects of Precipitate Element Addition on Microstructure and Magnetic Properties in Magnetostrictive Fe 83 Ga 17 alloy

• Published in: Journal of magnetics Vol. 21; no. 1; pp. 12 - 19
• Main Authors: Li, Jiheng, Yuan, Chao, Zhang, Wenlan, Bao, Xiaoqian, Gao, Xuexu
• Format: Journal Article
• Language: Korean
• Published: 2016
• Subjects: magnetostriction; microstructure; niobium carbide; magnetic property; Fe-Ga alloy; boron
• ISSN: 1226-1750; 2233-6656

The oriented $Fe_{83}Ga_{17}$ alloys with various contents of NbC or B were prepared by directionally solidification method at the growth rate of $720mm{\cdot}h^{-1}$. 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 $Fe_{83}Ga_{17}$ 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 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 $Fe_{83}Ga_{17}$ alloy due to the retarded domain motion resulted by precipitates.