Effect of spark plasma sintering temperature on structure and performance characteristics of Cu-20wt%W composite

Abstract

Spark plasma sintering (SPS) is a promising method for producing high performance Cu-W composite with high copper and low tungsten content, which has wide application space in some occasions. Cu-20 wt%W composite with uniformly distributed ultrafine tungsten particles has been successfully fabricated under different spark plasma sintering temperatures. This paper deals with the impact of spark plasma sintering temperature on structure and performance characteristics of the composite. The intrinsic relationship between sintering temperature, microstructure and properties was studied. The results showed that the optimum SPS sintering temperature of Cu-20 wt%W composite powders produced by spray drying method is 950 ℃. When the sintering temperature was increased, the content of copper-liquid would be increased, which could not only accelerate the rearrangement of tungsten particles but fill the holes to improve the performance of Cu-20 wt%W composite. However, a much higher temperature may lead to the sintering between tungsten particles, coarse copper net and the existence of copper vapor, ultimately resulting in the inhomogeneous distribution of tungsten and copper phases and the downward trajectory of the performance of the composite. The sintering mechanism was investigated and concluded with a detailed discussion. • The correlation in spark plasma sintering temperature, microstructure and properties was studied. • Cu-20wt%W powder by spray drying and hydrogen reduction has a core-shell structure and the size was as low as 50 nm. • The Cu-20 wt%W composite properties are optimized when a complete network structure with numerous dimples is formed.