The Effect Of Ce And Tb Doping On The Magnetostrictive Properties Of Fe-Ga-Al Alloy

Fe-Ga-Al alloy is a magnetostrictive material with better mechanical properties and machining properties than Fe-Ga alloy,and has been widely used in practical life.In this paper,the influence of addition of Al element on the magnetostrictive property of cast Fe₈₁Ga₁₉ alloy was studied,and the optimal composition point of Al element in Fe₈₁Ga₁₉ alloy was determined.On this basis,the influence of doping of rare earth elements Ce and Tb on the microstructure and magnetostrictive property of cast Fe-Ga-Al alloy was further explored.Based on the measurement of the magnetostrictive coefficient of Fe₈₁Ga_19-xAl_x（x=0～18 at%,Δx=2.0 at%）alloy,the Fe₈₁Ga_19-xAl_x（x=0,2.0,2.5,3.0,3.5,4.0 at%）alloy has been studied.The experimental results show that the alloy is dominated by A2 phase.The saturation magnetostrictive coefficient of the alloy is increased by Al addition,andλs reaches 202 ppm when x=3.5 at%.The microstructure of Fe₈₁Ga_19-xAl_x is columnar.The<100>orientation is enhanced.The saturation magnetostrictive coefficient of as-cast(Fe₈₁Ga_15.5Al_3.5)_100-yCe_y（y=0.0～1.0 at%,Δy=0.2 at%）decreases gradually with the increase of Ce doping amount.The phase composition of(Fe₈₁Ga_15.5Al_3.5)_100-yCe_y is still A2 phase,and the Ca Ga₂phase appears with the increase of Ce doping amount.The microstructure of(Fe₈₁Ga_15.5Al_3.5)_100-yCe_y is fine dendrite crystal,and the I₂₀₀/I₁₁₀ analysis shows that the microstructure has obvious preferred orientation.The EDS analysis and the variation trend of lattice constant,coerced force,saturation magnetization and residual magnetization with the doping amount of Ce indicate that Ce is not only precipitated at grain boundary,but also exists in the lattice of A2 phase.The saturation magnetostrictive coefficient of as-cast(Fe₈₁Ga_15.5Al_3.5)_100-zTb_z（z=0.00～00.30 at%,Δz=0.05 at%）decreases gradually with the increase of Tb doping content.The phase composition of(Fe₈₁Ga_15.5Al_3.5)_100-zTb_z alloy is mainly A2 phase.The EDS analysis show that Tb₆（Fe,Ga）₂₃ phase and Tb₂（Fe,Ga）₁₇ phase appear with the increase of Tb doping amount.The microstructure of(Fe₈₁Ga_15.5Al_3.5)_100-zTb_z is also fine dendrite crystal with obvious preferred orientation.The variation trend of lattice constant,coerced force,saturation magnetization and residual magnetization with Tb doping amount indicates that Tb is not only precipitated at grain boundary,but also exists in the lattice of A2 phase.