4. Phases in metal alloys

The following condensed phases may be present in a metal alloy.

• The liquid phase

  It always occupies the upper part of phase diagrams, towards high temperatures (unless, of course, the vapor phase is also represented). In the vast majority of cases, the liquid phase is unique, which means that, in the liquid state and at high temperatures, most metals are soluble in all proportions. However, in the event of strong repulsion between the metallic constituents, liquid demixing can occur in alloys, as in a vinaigrette containing an immiscible fatty and aqueous liquid.

• Primary solid solutions

  They adjoin the vertical axes of the pure bodies. These phases are isomorphic to the pure substances they border (they have the same crystalline structure)....