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