Two Metals Completely Soluble in the Liquid State and Completely Insoluble in the solid state

Two Metals Completely Soluble in the Liquid State and Completely Insoluble in the solid state
Technically, no two metals are completely insoluble in each other. However, in some cases the solubility is so restricted that for practical purpose they may be considered insoluble. The series of cooling curves for the pure metals and various alloys are shown in the figure given below .
the cooling curves for the pure metals A and B show a single horizontal line at their freezing points. As B is added to A, the temperature for the beginning of solidification is 60B. It can be seen that over a wide range of compositions, a portion of the cooling curve that shows the end of solidification occurs at a fixed temperature. The lower horizontal line at TE, shown dotted in the above figure, is known as eutectic temperature. In one alloy, the eutectic composition 40A-60B, complete solidification occurs at a single temperature, the eutectic temperature.
The melting points of the two pure metals, points M and N, are plotted on the vertical lines that represent the pure metals A and B. For an alloy having composition 80A-20B, the points showing the beginning of solidification T1 and end of solidification TE are plotted as shown. The same procedure is followed for all other alloys. The upper lines on the phase diagram connecting the points M, E and N is the liquidus line and shows the beginning of solidification. The point, at which the liquidus lines intersect, the minimum point E, is known as the eutectic point. TE is called the eutectic temperature and 40A-60B the eutectic composition. As solidus line is a continuous line connecting the melting points of pure metals, the complete solidus line is MFGN.