ABSTRACT
The determination of liquidus and solidus temperatures for a series of alloys in a system provides data for plotting isotherms on the liquidus and solidus surfaces. Such isotherms may be conveniently depicted on a projected view on the base of the space model. This chapter shows a liquidus projection or ‘liquidus plan’ for the Ag–Au–Pd system. The process of equilibrium solidification in the system may be illustrated by reference to an alloy of composition indicated by point X. At other temperatures within the liquidus solidus range, the tie-lines intersect the plane of the section at the composition point of the alloy but the extremities of the tie-lines do not lie in the plane. Thus a vertical section of this type through a ternary system differs essentially from a binary phase diagram since, in general, the tie-lines do not lie in the plane of the section.
