中文摘要：

采用铜模吸铸制备了厚度为0.8 mm,成分为Nd9Fe81-x-yTi4C2BxNby（x=11,13,15;y=0,4）的Nd2Fe14B/Fe3B型纳米复合永磁合金块体样品,研究了添加Nb对合金铸态组织及其晶化行为的影响,并测试了其磁性能。结果表明：在合金中添加4%（原子分数）Nb元素,不仅能抑制吸铸样品表面Nd2Fe23B3软磁性相、Nd1.1Fe4B4非磁性相和未知相的形成,导致Nd2Fe14B,Fe3B和α-Fe相的相对量增加,而且促使样品内部在非晶基体上形成了少量的Nd2Fe14B和α-Fe,Fe3B纳米晶。添加了Nb的合金吸铸样品表现出一定的硬磁性,其中Nd9Fe66Ti4C2B15Nb4吸铸样品具有最高的矫顽力（Hci=116.66 k A·m-1）;添加4%（原子分数）Nb使得合金在晶化过程中由原来的异相同温一步晶化转变为两步晶化,且初始晶化温度Tx均明显降低,两个放热峰的ΔTpx均增大。

英文摘要：

The bulk samples of Nd2Fel4 B/Fe3B type nanocomposite permanent alloys Nd9Fe81-x-y Ti4C2BxNby （x=11, 13, 15; y = 0, 4） with the thickness of 0.8 mm were prepared by copper mold suction casting. The Influences of Nb doping on the microstructures and crystallization behavior of the as-cast bulk samples were studied. The results showed that not only Nd2Fe23B3, Nd1.1 Fe4B4 and an unknown phase were suppressed for the surface of the samples with 4% Nb doping, resulting the volume fractions of Nd2Fe14B, Fe3B and α-Fe increased largely, but also a small amount of nanocrystalline Nd2Fe14B, Fe3B and α-Fe appeared in the amorphous matrix for their interior. The as-cast Nb-doped bulk samples exhibited some hard magnetic, and the Nd9Fe66Ti4C2B15Nb4 had the highest coercivity of Hci 116.66 kA·m-1 among them. The crystallization process changed from one step for Nb-free alloys to two steps for Nb-doped ones. The initial crystallization temperatures of the Nb-doped alloys decreased significantly, and the △Tpx value of the two exothermic peaks on the DSC curves increased, comparing with the Nb-free alloys.