INTRINSIC MAGNETOSTRICTION OF Tb-Dy-Fe-Co ALLOY
Tb-Dy-Fe-Co合金本征磁致伸缩性能

The distribution of Co, the intrinsic magnetism and magnetostriction of quaternary Tb-Dy-Fe-Co alloy were investigated. The SEM image showed the matrix (Laves phase) and the rare-earth (RE) rich phase in the annealed samples. The Co content (atomic fraction) in the RE rich phase was 21.18%, much higher than that in the matrix (9.36%). XRD patterns showed that Co partial substitution for Fe did not change the structure of MgCu2-type cubic Laves phase, contributing to the giant magnetostriction. Curie temperature Tc was increased remarkably with Co addition, resulting in wider operating temperature. The magnetocrystalline anisotropy compensation by Co addition was beneficial to improving the magnetostriction in low field. The solidified orientation influences the testing of intrinsic magnetostriction. In order to ensure the accuracy in the measurements, the equiaxed Tb-Dy-Fe-Co samples were prepared. The saturated magnetostrictive constant λs was tested. λ111 and λ100 were calculated by the cleavage of (440) diffraction peak of Laves phase. Compared with Terfenol-D alloy, λ111 in the Co-doped sample decreased slightly, but λ100 increased evidently and λs almost remained unchanged.