Tb0.3Dy0.7Fe1.95-xNbx (x=0, 0.03, 0.06, 0.09) 合金的组织与磁致伸缩性能

Microstructure and Magnetostriction of Tb0.3Dy0.7Fe1.95-xNbx (x=0, 0.03, 0.06, 0.09) Alloys

摘要:

采用高真空电弧炉制备了Tb0.3Dy0.7Fe1.95-xNbx (x=0, 0.03, 0.06, 0.09) 合金，研究了该系列合金的晶体结构、微观组织及磁致伸缩性能。结果表明：添加Nb元素后的Tb0.3Dy0.7Fe1.95-xNbx (x=0.03, 0.06, 0.09) 合金基体相结构仍保持为MgCu2 (C15型) 立方Laves相，添加Nb后Tb0.3Dy0.7Fe1.95-xNbx合金基体相晶格常数几乎不变。Nb在基体相RFe2中和富Re相中都不溶，但在x=0.03时的RFe3相中微溶而形成Re(Nb,Fe)3相。初生相NbFe2（C14型）相的形成使凝固液体富稀土从而抑制了RFe3有害相形成。六方结构的NbFe2在与自身结构不同的RFe2（C15型）中不溶而单独成为一相存在于RFe2基体上。Nb的添加量x对磁致伸缩的影响很大，微量（x=0.03）Nb的添加有效抑制了RFe3有害相的生成而使得磁致伸缩性能提高最大，但当Nb含量继续增大时，由于顺磁相NbFe2和富Re相的析出影响了基体磁-弹性交互作用而使磁效伸缩性能下降。但相对于Tb0.3Dy0.7Fe1.95母合金都有少量提高。

Abstract:

The Tb0.3Dy0.7Fe1.95-xNbx (x=0, 0.03, 0.06, 0.09) alloys were prepared by a high-vacuum arc melting furnace. The crystal structure, microstructure and magnetostriction of the alloys were studied. Results demonstrate that after Nb addition the matrix phase of the Tb0.3Dy0.7Fe1.95-xNbx (x=0.03, 0.06, 0.09) alloys consists predominantly of the cubic Laves phase with MgCu2 (C15-type) structure, and the lattice parameter of the Laves phase in the alloys is least affected. Nb is soluble negligibly in the matrix RFe2 and Re-rich phases, but dissolved in the RFe3 phase and formed into Re(Nb,Fe)3 phase when x=0.03. The formation of the NbFe2 phase as the primary phase make the solidifying liquid become rich in rare earths and suppress the formation of the deleterious RFe3 phase. The hexagonal C14-type Laves phase NbFe2 does not dissolve into the matrix RFe2 (C15-type) phase. The concentration of the element Nb affects the magnetostriction significantly. The improvement in magnetostriction is maximum for the element-added alloy with a low concentration of the element Nb (x=0.03) as compared to the parent alloy Tb0.3Dy0.7Fe1.95. However, the decrease in magnetostriction occurs with the increasing of Nb content which is due to the formation of paramagnetic phases NbFe2 and Re-rich phases. Whereas the magnetostriction has a little improvement as compared to the parent alloy Tb0.3Dy0.7Fe1.95.