Multiple impacts of trace Tb addition on the secondary recrystallization and magnetostriction of Fe-Ga alloy thin sheet

Fe-Ga alloys are potential for the new-generation magnetostrictive applications in sensors, transducers, and actuators due to the combination of large magnetostriction and good structural properties.<001>-oriented Fe-Ga sheets with large magnetostriction are required for improving the conversion efficiency under the ultra-high frequency magnetic field. Trace Tb element doping can simultaneously improve the magnetostriction and ductility of Fe-Ga alloy. However, the impact of trace Tb doping on the microstructure and magnetostriction of Fe-Ga thin sheets is an open question. In this paper, the effects of trace Tb addition on the secondary recrystallization and magnetostriction of Fe-Ga thin sheets are systematically studied by comparing the characteristics evolution of precipitation, texture, and nanoinclusions. The results indicates that trace Tb addition accelerates the secondary recrystallization of Goss grains due to the combined action of the bimodal size distributed precipitates, smaller grains, and more HEGBs in primary recrystallization. After quenching at 900 °C, the magnetostriction value in 0.07%Tb-doped Fe81Ga19 thin sheets increases 30% than that of Fe81Ga19 thin sheets. The increase of magnetostriction is attributed to the decrease in the number of Tb-rich precipitates and the higher density of the nanometer-sized modified-D03 inclusions induced by the dissolving of trace Tb elements after quenching. These results demonstrate a simple and efficient approach for preparing Fe-Ga thin sheets with excellent magnetostriction by a combination of trace RE element addition and conventional rolling method.