Effects of the third element additions on phase constitution and magnetostriction of Fe-Ga alloys

Phase constitutions and magnetostrictions of Fe₈₁(Ga_1-xM_x)₁₉(x=0, 0.1, 0.2, 0.3; M=Si, Ge, Sn) alloys were studied. The results indicated that all of Fe-Ga-Si and Fe-Ga-Ge ternary as-cast and quenched states kept a disordered A2 phase structure (Fe₈₁Ga₁₉). Substitution of Si or Ge for Ga will not noticeably reduce magnetostriction for x=0.1. Wherein, the saturation magnetostriction of quenched Fe₈₁(Ga_0.9Ge_0.1)₁₉ alloy was much higher than that of quenched Fe₈₁Ga₁₉ alloy. Further increasing Si and Ge contents, the saturation magnetostrictions of Fe₈₁(Ga_1-xM_x)₁₉(M=Si, Ge) decrease sharply. The as-cast and quenched Fe₈₁(Ga_1-xSn_x)₁₉(x=0.1, 0.2, 0.3) comprised FeSn(Ga) phase and A2 matrix. With increasing Sn content, the saturation magnetostrictions of as-cast and quenched Fe-Ga-Sn alloys decreased owing to the appearance of much more non-ferromagnetic FeSn(Ga) phase. The maximum saturation magnetostriction value observed in the as-cast Fe₈₁(Ga_0.9Sn_0.1)₁₉ alloys was 41 × l0^-6, slightly higher than that of the as-cast Fe₈₁Ga₁₉ alloy.