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

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 indicate that trace Tb addition accelerates the secondary recrystallization of Goss texture 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 0.07at%Tb-doped Fe₈₁Ga₁₉ thin sheets increases by 30% to that of Fe₈₁Ga₁₉ thin sheets. The increase in 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 a large magnetostrictive coefficient by a combination of trace RE element addition and conventional rolling method.