Study on the precipitates formed by Double Glow Plasma Surface Alloying with tungsten-molybdenum

Due to the slow cooling rate in the alloying furnace, large amount of britt le precipitates appear in the alloyed layers which are formed by the DGPSA (Double Glow Plasma Surface Alloying) with tungsten-molybdenum. It causes t he mechanical properties of the samples to be seriously degraded. Qualitati ve phase analysis reveals that they are mainly composed of the p-phase, and a small amount of carbide, M6C. In this paper the microstructure and therm odynamic factors of the precipitates are exhaustively investigated. There a re two transformation noses in the isothermal transformation (IT) diagram o f the precipitates. As a major object of this work, an effective measure is offered to depress the deposition of the precipitates.