Effect of Vacuum Degree on Microstructure and Properties of Molybdenum Vanadium Aluminum Alloy from Vacuum Induced Refining

In order to improve alloy quality by removing gas, impurities and inclusions from primary molybdenum-vanadium alloy prepared by thermite method, improving element distribution, and reducing crystallization defects and segregation, the vacuum induction melting furnace is used to conduct secondary vacuum refining, and the effects of different vacuum degrees on the microstructures and properties of molybdenum vanadium aluminum ternary intermediate alloys after refining are discussed. The results show that with the increase of vacuum degree, the contents of the impurity elements in the refined alloy are declined and tend to be stable gradually, and that the oxidation degree of the alloy decreases obviously. The alloy refined consists of V_0.5Mo_0.5, Al₅Mo and AlMo₃ phases. When the vacuum degree is 50 Pa, the microstructure of the alloy is the most uniform and the grain is fine, the density and hardness are the best. When the vacuum degree further increases, the grains of the microstructure coarsened, and the density and hardness grows extremely slowly. This research is to lay foundation for the production of high quality molybdenum vanadium aluminum ternary intermediate alloys.