Effects of Precipitate Element Addition on Microstructure and Magnetic Properties in Magnetostrictive Fe₈₃Ga₁₇alloy

Abstract

The <100> oriented Fe 83 Ga 17 alloys with various contents of NbC or B were prepared by directionally solidification method at the growth rate of 720 mm·h. 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 Fe 2 B 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 Fe 83 Ga 17 alloy due to the retarded domain motion resulted by precipitates.

Non-destructive Measurement of Magnetic Properties of Claw Pole

“…It is also possible to obtain the magnetization curve and hysteresis loop using a hollow square or other closed geometrical shape [8]. The effect of precipitate element addition on the magnetic properties of the magnetostrictive Fe 83 Ga 17 alloy was studied with ring samples: the results showed that the coercivity significantly increased with the addition of such elements [9]. Addition of boron caused undesirable deterioration of the magnetic properties of a permalloy, while the effects of magnesium and calcium on its magnetic properties were small [10].…”