Effect Of The Ternary Element(B、Cu、Al) Additions On Phase Constitution And Magnetostriction Of Fe-Ga Alloys

The efffect of ternary element additions and preparation on microstructure and magnetostiction of Fe-Ga alloy was studied systematically in this paper. Foundry alloy Fe81Ga19-xCux (Cu=1,2,3),Fe81Ga19-xAlx(x=2,3,5) and (Fe0.81Ga0.19)100-xBx(x=1,5,10) were prepared by electric vacuum furnace melting,then casting molding to Φ7mm alloy bar. The Fe-Ga alloy under certain solidification rate was prepared by zone melting directionally solidified technique,and quenching at800℃in3hours.As a comparison,systematically studied the microstructure and magnetostrictive properties of the Fe81Ga19alloy which produce by the same experimental method.Finally draw the following results:After directionally solidified,the crystallite dimension of Fe81Ga19alloy is larger than in as-cast.The structure of alloy is composed of large size columuar crystals,which preferred growth along directional solidification direction.The I(200)/(110) of alloy is90.96%,and the saturation magnetostriction is189ppm.After heat treatment,the growth direction get back into <110> orientation,and the broadwise subgrain boundary of alloy are disappeared.The saturation magnetostriction is195ppm,and the Low field response is faster.Adding Cu as ternary element,Fe81Ga19-xCux(x=1,2,3) alloy retained disorder A2phase shructure.There are some Cu separate out at crystal boundary in Fe81Ga16Cu3alloy,and the precipitated phase get back into matrix by solid solution form after quenching.After directional solidified,the same as Fe81Ga19alloy,the crystallite dimension of Fe81Ga19-xCux(x=1,2,3) alloy is larger than in as-cast,and preferred growth along directional solidification direction.The saturation magnetostriction of Fe81Ga19-xCux(x=1,2,3) alloy and Fe81Ga19-xAlx(x=2,3,5) alloy has significantly improved.And after thermal treatment, the Low field response is fast, the maximum is the Fe81Ga18Cu alloy in directional solidification after thermal treatment,which is57ppm. Adding Al as ternary element,Fe81Ga19-xAlx (x=2,3,5) alloy retained disorder A2phase shructure.The saturation magnetostriction of Fe81Ga19-xAlx(x=2,3,5) alloy increase with increating Al concent.Fe81Ga19-xAlx(x=2,3,5) alloy has Al-Ga solid solution frist preprated in both as-cast and directional solidification,whichmakes the magnetostiction of Fe-Ga alloy degradation. After thermal treatment,the Al atoms distributed evenly in substrate alloy,and the magnetostiction is improved.Compare with as-cast,after directional solidified,the saturation magnetostriction of Fe81Ga19-xAlx(x=2,3,5) alloy has significantly improved.And after thermal treatment, the Low field response is fast.The maximum is174ppm in Fe81Ga14Al5in directional solidification after thermal treatment.It is a little lower than the maximum of Fe81Ga19alloy in directional solidification after thermal treatment,which is195ppm.After directionally solidified,the crystallite dimension of (Fe0.81Ga0.19)100-xBx(x=1,5,10) alloy is larger than the alloy of as-cast,and the structure of alloy is composed of large size columuar crystals,which preferred growth along directional solidification direction.(Fe0.81Ga0.19)100-xBx alloy retained disorder A2phase shructure,only little B solve slightly in Fe-Ga alloy,the rest of B form the Fe2B phase with Fe atoms.So (Fe0.81Ga0.19)100-xBx alloy composed by A2phase,simple substance of B and Fe2B phase.Because the Fe2B phase will be formed before Fe-Ga alloy,the content of Ga in alloy matrix rise,the Ga phase of enrichment showed in both as-cast and directional solification,and it discreased the magnetostiction of alloy.After thermal treatment,the Ga phase of enrichment disappeared,magnetostiction improved,and Low field response is fast,the maxmum of (Fe0.81Ga0.19)90B10alloy in directional solidification after thermal treatment in100KA/m,which is70ppm.