Microstructure regulation mechanism of CuW composites prepared by aluminothermic coupling with magnesiothermic reduction

CuW composites are widely used in high voltage transmission, electronic information, aerospace and other cutting-edge fields. At present, the preparation methods of CuW composites based on powder metallurgy have the defects of uneven microstructure and low density. Reducing the size of tungsten particles in the CuW composites can significantly improve the microstructure uniformity and density. In this paper, an innovative idea for regulating the microstructure of CuW composites by aluminothermic coupling with magnesiothermic reduction was proposed. The thermodynamics and dynamics of the reaction system for preparation of CuW composites by this method were studied, and the microstructure of CuW composites were systematically analysed and evaluation. The researches show that the inclusion in CuW prepared by aluminothermic reduction was Al 2 O 3 , and the inclusion in CuW prepared by aluminothermic coupling with magnesiothermic reduction was MgO·Al 2 O 3 . The addition of magnesium to the reducing agent had an obvious refining effect on the tungsten particles. The mechanism was that magnesium was converted into magnesium vapor during the rapid heating process of the system, and the gas-solid, gas-liquid-solid reaction occurred with tungsten oxide to generate smaller tungsten particles. With an increase of magnesium content, the average size of tungsten particles in the microstructure of CuW gradually decreased from 2.38 μm to 0.82 μm, and the microstructure uniformity increased from 56.26% to 76.96%.