Preparation of fine-grained Mo[sbnd]W solid solution alloys with excellent performances.

Molybdenum‑tungsten (Mo W) alloy composed of molybdenum (Mo) and tungsten (W), is a popular high-temperature material. In this paper, a new method for preparing Mo W solid solution alloy has been proposed. To resolve the problem of low extent of solid solution and large grain size, ultrafine Mo W composite powder and Mo-W-Al 2 O 3 composite powder were synthesized by spray drying combined with carbothermic pre-reduction and deep reduction by hydrogen. The results show that the method can effectively promote the formation of Mo W solid solution, and the particle sizes of the four composite powders (Mo-30 W, Mo-50 W, Mo-30 W-0.5Al 2 O 3 , Mo-50 W-0.5Al 2 O 3) were 50–200 nm. After sintering at 1600 °C, all alloys can achieve a high relative density (97%-98%) while retaining a small grain size and good comprehensive properties. Meanwhile, the effect of Al 2 O 3 doping on the sintering performance of Mo W alloys was also investigated in detail. The results showed that doping of 0.5 wt%Al 2 O 3 reduced the grain size of Mo W alloy from 5 μm to 3 μm. In addition, the hardness of Mo-30 W alloy and Mo-50 W alloy were increased to 471 HV and 534 HV, while the bending strength was increased to 612 MPa and 647 MPa, respectively. • A new method for preparing Mo W solid solution alloy has been proposed. • Fine-grained Mo W solid solution alloy was synthesized by currently prepared ultrafine Mo W composite powder. • Spray drying promoted the formation of complete solid solution. • Alloy with 0.5 wt% Al 2 O 3 exhibited excellent bending strength and hardness. [ABSTRACT FROM AUTHOR]