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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。
Tb0.3Dy0.7Fe1.95-xNbx (x = 0,0.03,0.06,0.09) alloys were prepared by high vacuum electric arc furnace. The crystal structure, microstructure and magnetostrictive properties of the alloys were studied. The results show that the phase structure of Tb0.3Dy0.7Fe1.95-xNbx (x = 0.03,0.06,0.09) alloy remains as MgCu2 (C15 type) cubic Laves phase after addition of Nb, and Tb0.3Dy0.7Fe1 .95-xNbx alloy matrix phase lattice constant almost unchanged. Nb is insoluble in both the base phase RFe2 and the Re-rich phase, but is slightly soluble in the RFe3 phase at x = 0.03 to form a Re (Nb, Fe) 3 phase. The formation of the NbFe2 (C14) phase of the nascent phase enriched the solidified liquid and inhibited the formation of the detrimental phase of RFe3. The hexagonal structure of NbFe2 is insoluble in RFe2 (C15 type) which is different from its own structure and exists alone as one phase on the RFe2 matrix. The addition amount of Nb has a great influence on the magnetostriction. The addition of trace amount (x = 0.03) Nb effectively inhibits the formation of the detrimental phase of RFe3 and maximizes the magnetostriction. However, when the Nb content continues to increase, The precipitation of the paramagnetic phase NbFe2 and the Re-rich phase affects the magnetic-elastic interaction of the matrix and decreases the magnetostrictive properties. However, a slight increase relative to Tb0.3Dy0.7Fe1.95 master alloy.