中文摘要：

在300 K/cm的温度梯度条件下,实施不同抽拉速率下的Ni Al-1.5at%W共晶合金定向凝固。分析研究抽拉速率对W纤维相相间距、纤维相尺寸的影响规律。并使用盐酸双氧水溶液对Ni Al基体进行选择性溶解,制备出当量直径小于500 nm的钨纤维丝束。结果表明：随着抽拉速率的增大,W纤维相截面形状圆度增加,W纤维相相间距和W纤维相截面当量直径均减小,两者的比值在6.12到7.54之间。经选择性溶解获得的W纤维具有多样的三维形貌,呈现出薄带状、珍珠串状和搭接状,发现其形貌与抽拉速率有关。

英文摘要：

Under a temperature gradient of 300 K/cm, Ni Al-1.5at%W eutectic samples were directionally solidified at different drawing rates. The effect of the drawing rates on the spacing and the size of W fiber phases was analyzed. In addition, the Ni Al matrix was selectively etched by a solution of HCl：H2O2 to prepare the tungsten fiber filaments with the equivalent diameter less than 500 nm. The results show that with the drawing rate increasing the roundness of W fiber phase cross-section increases, while the spacing as well as the equivalent diameter of W fiber phase both decreases, and the ratio between them is in the range of 6.12 to 7.54. The tungsten fibers obtained by selective dissolution have the diversiform three-dimensional morphologies, such as the thin strip, pearl string and lapping state, and it is found that those shapes are related to the drawing rate.