Inter-crossing of two-phase equilibria

In the system Ti-W the continuous solid solution stable at high temperature decomposes on lowering the temperature through a eutectic-type reaction into 

Extreme cases of solid solubility are shown in Fig. 2.11. In particular notice the system Au-Si for which, owing to a negligible solubility in the solid state, the terminal phases are practically coincident with the pure elements. 

Several pairs of elements show the behaviour exemplified by these figures. These have also been collected in the map of Fig. 2.8. 

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