Binary alloy idealized phase diagram

Figure 5. Idealized phase diagram for a binary alloy. The liquidus slope m and equilibrium segregation coefficient k are defined in the text.

Figure 13.2 shows two temperamre-composition phase diagrams with single eutectic points. The left-hand diagram is for the binary system of chloroform and carbon tetrachloride, two liquids that form nearly ideal mixmres. The solid phases are pure crystals, as in Fig. 13.1. The right-hand diagram is for the silver-copper system and involves solid phases that are solid solutions (substimtional alloys of variable composition). The area labeled s is a solid solution that is mostly silver, and s is a solid solution that is mostly copper. Tie lines in the two-phase areas do not end at a vertical line for a pure solid component as they do in the system shown in the left-hand diagram. The three phases that can coexist at the eutectic temperature of 1,052 K are the melt of the eutectic composition and the two solid solutions.

Germanium appears to form no carbide, but it alloys with many metals and metalloids. A complete tabulation of intermetallic compounds (as of 1968)1 fists 152 compositions, from which the representative metal germanides of Table 5 have been abstracted. The relation of Ge with Si is unique a continuous series of solid solutions is formed, and the two liquids also form ideal mixtures. About eighty ternary intermetallic compounds are known, and phase diagrams for many of the binary and ternary systems have been reportedly. 

Phase diagram for the Ge-Si system. The Ge is on the left in this diagram and the liquid-solid two-phase region is somewhat fatter than in the calculated case, possibly due to small departures from ideality of the system. (Reprinted from Massalski, T.B., Handbook of Binary Alloy Phase Diagrams, Vols 1, 2, and 3, ASM, 1990. Reprinted with permission of ASM International. All rights reserved.)... 

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