X
1. For bulk composition X, liquid cools
to liquidus at 1600°C
P = 1 atm
2. Fo begins
to crystallize
3. Liquid composition moves directly
away from Fo
4. Liquid composition reaches cotectic; Di
begins to crystallize with Fo
5. Co-precipitation of Fo + Di causes liquid
composition to move down cotectic curve
6.
Liquid composition reaches ternary eutectic at 1270°C; An begins to crystallize with Di + Fo
7. Liquid is consumed; An +
Di + Fo cool below 1270°C