中文摘要：

制备具有优良机械性能Nb3Al前驱线是得到NbAl超导长线，继而制备实用化高场磁体的基础．本文选用Mg的含量分别为1．08wt．％和4．48wt．％的两种Al合金棒作为Al芯，不同壁厚的Cu管作为包套，利用套管法分别制备了两组不同芯丝数的NbAl前驱线．通过观察和测量两组前驱线芯丝形状和硬度的变化，以及对前驱线拉伸曲线和拉伸后断口形貌的分析，研究了影响前驱线机械性能的因素，提出了改善芯丝加工性能的方案．结果表明：Mg含量和Cu包套的壁厚对前驱线的机械性能有很大的影响，选择合适的A1合金棒以及包套，可以得到芯丝均匀，具备良好机械性能的Nb3Al前驱线，49芯前驱线经过扩散热处理后得到了15．7K的超导转变起始温度．

英文摘要：

It is important to obtain the Nbs Al precursor wires with excellent mechanical properties and continuously uniform filaments, so as to fabricaing practical magnets with long Nbs Al superconducting wires for high field application. In this paper, two kinds of multifilaments wires were fabricated with different Al alloying rod and Cu sheath by RIT method （Rod in Tube）. The effects of Mg content and the thickness of Cu sheath on the mechanical properties of Nb3 Al precursor wires were investigated by measuring the hardness variation, analyzing the morphologies of cross-sections and the tensile fracture of different multifilaments wires and the routes to increase the plasticity of the filaments are proposed. The reasults suggest that the content of Mg and the thickness of sheath have obvious effects on the mechanical properties of Nb3 AI precursor wires. The wires will provide excellent mechanical properties and get uniform Al filaments if the suitable A1 alloy and sheath are chosen. The Tcomset of 49-filament wire after diffusion heat treatment reached 15.7 K.