Experimental investigation of phase equilibria in the Co–W–V ternary system

The phase equilibria in the Co–W–V ternary system were experimentally investigated by optical microscopy (OM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. Three isothermal sections of the Co–W–V ternary system at 1100 °C, 1200 °C and 1300 °C were determined, and no ternary compound was found in this system. In addition, a novel phenomena induced by the liquid phase separation in the Co–W–V alloys was firstly discovered, suggesting that a stable liquid miscibility gap exists in the Co–W–V ternary system. The newly determined phase equilibria and firstly discovered phase separation phenomena in the Co–W–V system will provide important information for the development of Co–W based alloys.

► Three isothermal sections of the Co–W–V ternary system at 1100 °C, 1200 °C and 1300 °C were determined.
► No ternary compound was found in the Co–W–V ternary system.
► A stable liquid miscibility gap is newly discovered in the Co–W–V ternary system.
► This work is of great essence to establish the thermodynamic database for the Co-based alloys.