Effect of tungsten tantalum pre-alloying on the sintering structure of 90(W-Ta)-Ni-Fe alloy

Abstract The intrinsic brittleness of tungsten limits the improvement on the comprehensive mechanical properties of tungsten alloys. Starting from the perspective of solid solution toughening, this study innovatively used tungsten-tantalum particles instead of tungsten particles as the sintered core to prepare 90(W-Ta)-Ni-Fe alloy. Tantalum forms a BCC solid solution with tungsten in the process of high-energy ball milling. During the vacuum sintering process, tantalum precipitated and reacted with the matrix to form acicular phase. This precipitation process reduces the liquid phase sintering temperature of the tungsten alloy and refine the tungsten particles. The microstructure of the sintered alloy is composed of tungsten particles, matrix phase, intermediate phase, acicular precipitated phase and oxides. The solid solution of tantalum increases the hardness and reduces the modulus of the tungsten particles. The hardness and modulus of the matrix phase are increased due to the influence of the acicular precipitation phase. These findings indicate that the solid solution of tantalum has the potential to improve the comprehensive mechanical properties of tungsten heavy alloys.