Preparation and properties of W-Mo-Cu composite using solution combustion synthesized W[sbnd]Mo solid solution nanopowder

Abstract

Due to the high melting points of W and Mo, WMo solid solution powder needs to be prepared at extremely high temperatures using W and Mo elemental powder. Herein, the nano-sized WMo solid solution powders with different Mo content were successfully fabricated by solution combustion synthesis. And then the WMo nanopowders were used to prepare W-Mo-Cu composites by liquid phase sintering. The results revealed that the addition of Mo can promote the densification of the W/Cu composite powders and improve the microhardness of the WCu composites, while the conductivity will inevitably be reduced. When the amount of Mo addition is <10 wt%, the Mo element is uniformly distributed in the W particles in the W-Mo-Cu composites, while the segregation of Mo was observed when Mo addition >10 wt% due to inhomogeneous Mo distribution in the starting powder. Meanwhile, the Mo segregation region may be responsible for the formation of Mo2C phase in (W20Cu)-30Cu, due to the susceptibility of Mo to react with carbon. During the arc ablation process, the Mo in the W particles dissolves into the liquid-phase Cu, increasing the viscosity and reducing the splashing of the Cu.