Effect Of Co And Tb Addition On The Structure And Magnetic Properties Of Fe-Ga Alloys

The effect of ternary addition of Co and quaternary addition of rare earth element Tb on magnetostrictive properties of Fe₈₃Ga₁₇ alloy was investigated.The Fe_83-xCo_xGa₁₇(x=0-10 at%)and(Fe_81.5Co_1.5Ga₁₇)_100-yTb_y(y=0-0.20 at%)alloys were smelted in a non-consumable vacuum arc furnace.The microstructure of the alloys were analyzed by XRD,SEM and TEM.Magnetostrictive strain,magnetization property,Curie temperature and hardness of alloy were measured by Akulov instrument,VSM and Vickers hardness tester.The results show that Fe-Co-Ga and Fe-Co-Ga-Tb alloys are unordered intact cubic structures,Co element doped with Fe elements in the alloy and high solid solution,the solid solubility of Tb element is small in Fe-Co-Ga alloy.Fe_83-xCo_xGa₁₇ series of alloys are columnar and the addition of Co element promotes the preferential orientation of the alloys.Tb element precipitates at the grain boundary,leading to grain refinement and dendritic crystal formation.The saturation magnetostrictive coefficient of Fe_81.5Co_1.5Ga₁₇ alloy doped with 1.5at%Co is the highest,reaching 195 ppm,which is 38%higher than that of Fe₈₃Ga₁₇.(Fe_81.5Co_1.5Ga₁₇)_99.90Tb_0.10 alloy has the best saturation magnetostriction coefficient of217 ppm,which is increased by 53%compared with Fe₈₃Ga₁₇ alloy.The saturation magnetization of Fe_81.5Co_1.5Ga₁₇ alloy in parallel direction can reach 195.60 emu/g when the doping of Co element is 1.5 at%.The Curie temperature of the alloy increases with the increase of Co element.When Co element is doped with 3.5 at%,the Curie temperature of the alloy reaches 1010 K,while Tb element has no effect on the saturation magnetization and Curie temperature of Fe-Co-Ga alloy.The doping of Co is of great significance to the saturation magnetostrictive coefficient of Fe-Ga alloy and the increase of Curie temperature for the application of magnetostrictive materials.The increase of Curie temperature can widen the service temperature range of magnetostrictive materials,therefore has the important project development value.