Al–Co–W fusion diagram in the Co–CoAl–W part

The fusion diagram of the Al–Co–W system in the Co–CoAl–W part was drawn using optical light, differential thermal, X-ray diffraction and electro n microprobe analysis data. The alloys were prepare d by arc melting. No ternary intermediate phase was foun d in this partial system above 900°C. The phase equilibria between CoAl and W were established with the peritectic reaction L+W↔CoAl at 1650oC. The Co–CoAl–W fusion diagram has two isothermal three-phase fie lds corresponding to four-phase invariant reactions with participation of liquid: L ↔Co+CoAl+Co7W6 (1380°C) and L+W↔Co7W6+CoAl (1490°C). The solidus and liquidus surface projections and the ve rtical sections for 75 at.% Co and equiatomic Al and W are presented and compared with the isothermal sect ions at 1200°C and 900°C reported earlier.