Crystallization Behavior of Amorphous Fe-Tb-M (M=Si or Al) Alloys and High Magnetostriction of their Crystallized Phases
The addition of 2.5 at% Si or Al to Fe_2Tb causes the formation of an amorphous single phase and the glass formation range extends up to 15 at% Si or Al which is the maximum additional amount in the present study. The amorphous (Fe_2Tb)_<97.5>M_<2.5> (M=Si or Al) alloys crystallize through two stages consisting of Am→Fe_2Tb+Am→Fe_2Tb+unknown compound. The Fe_2Tb phase in coexistent with the amorphous phase has a very fine spherical morphology with a particle size of 5 to 20 nm. The additional Si or Al element is enriched into the unknown compounds. The coexistent state of the nanocrystalline Fe_2Tb and amorphous phases extends over the temperature region of about 300 K because of the high thermal stability of the remaining amorphous phase. The high thermal stability of the amorphous phase and the formation of the nanoscale Fe_2Tb grains are presumably due to the necessity of the redistribution of Si or Al into the remaining amorphous phase. The best magnetostrictive properties of high σ_<1440>, low H_c, high λ_s and high λ/H were obtained in the coexistent nanocrystalline Fe_2Tb and amorphous phases and the phase transition into Fe_2Tb and unknown compounds caused the depression of the magnetostrictive properties.
- Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 39 (2), 147-153, 1994-03-25