Effect of In, Ge addition on magnetostriction of Fe₈₁Ga ₁₉ alloy

Phase structure, microstructure and magnetostrictions for In, Ge element doped Fe₈₁(Ga_1-xY_x)₁₉ (Y = In, Ge; z =0, 0.1) alloys were studied. The results show that a single phase of A2 with an equiaxial morphology is observed in Fe₈₁Ga₁₉ alloy under as-cast and quenched states. While In-rich phase distributing in grain boundary and A2 matrix are comprised for the Fe₈₁(Ga _0.9In_0.1)₁₉ alloys and the amount of In-rich phase reduces after quenching. The Ge doped as-cast and quenched Fe ₈₁(Ga_0.9In_0.1)₁₉ alloys keep the A2 structure with smaller lattice constant. A large number of dendrite exhibit in as-cast Fe₈₁(Ga_0.9 Ge_0.1)₁₉ alloy which disappeared and changed to the equiaxial morphology by quenching. The saturation magnetostriction λ₅ of as-cast Fe ₈₁Ga₁₉ alloys is 3.3 × 10^-5 and increases to 7.2 × 10^-5 after quenching. The saturation magnetostriction of Fe-Ga alloys is reduced by addition of In. The λ₅ values of the quenched Fe₈₁(Ga_0.9In_0.1)₁₉ alloy is two times higher than that of the as-cast one. The saturation magnetostriction of Fe-Ga alloys is also reduced by doping Ge. Compare with the magnetostriction of as-cast Fe₈₁(Ga_0.9Ge _0.1)₁₉ alloy, that of quenched one increases about twice.