Inhibition force of precipitates for promoting abnormal grain growth in magnetostrictive Fe₈₃Ga₁₇-(B,NbC) alloy sheets

Inhibition force of precipitate particles for promoting abnormal grain growth in magnetostrictive Fe₈₃Ga₁₇-(B,NbC) alloy sheets was investigated in this study. After a continuous heating and a high-temperature annealing, the Fe₈₃Ga₁₇ + 0.5 at% B alloy sheets do not occur significant abnormal grain growth. Correspondingly, textures of {111}<112> and {100}<001> in addition to the Goss texture are obtained in the final annealed alloy sheets. By contrast, after the same annealing processes, the size of {110} textured grains is very large in the final annealed Fe₈₃Ga₁₇ + 0.5 at% NbC alloy sheets due to the abnormal grain growth, which results in a sharp Goss texture. BN precipitates were introduced into Fe₈₃Ga₁₇ + 0.2 at% B alloy sheets by nitriding annealing at 800 °C for 2 min under NH₃ atmosphere. The abnormal grain growth of Goss grains is achieved in 0.2 at% B-doped Fe₈₃Ga₁₇ alloy sheets after a high-temperature annealing, which is attributed to the enhanced inhibition force by introducing BN precipitates. During the recrystallization annealing process, Fe₂B precipitates is easy to coarsen and decompose at high temperature due to the low thermal stability, resulting in a decrease or even disappearance of the inhibition force. For NbC and BN precipitates, the thermal stability and hardness of particles are both better than those of Fe₂B precipitates, leading to strong inhibition force. Because of the preferred Goss texture, the magnetostriction of 2.05 × 10⁻⁴ and 1.81 × 10⁻⁴ is obtained in the secondary recrystallized Fe₈₃Ga₁₇ + 0.5 at% NbC and Fe₈₃Ga₁₇ + 0.2 at% B alloy sheets, respectively.