1. Consider a Cu–80% Ag alloy. (See Figure) Determine

(a) if the alloy is hypoeutectic or hypereutectic,

(b) The composition of the first solid to form during solidification,

(c) The amounts and compositions of each phase at 780°C,

(d) The amounts and compositions of each phase at 778°C,

(e) The amounts and compositions of each microconstituent at 778°C, and

(f) The amounts and compositions of each phase at 25°C. 

BINARY EUTECTIC SYSTEMS Temperature (C) 1200 A 1000 800 a 600 400 C 20 PHYSICAL METALLURGY (1) - 2012 R.EQRA Composition (at% Ag) 40 60 80 100 2200 Liquidus Liquid 2000 -Solidus a +L 1800 F 1600 B 779C (TE) B+L E G 8.0 (CE) 71.9 91.2 1400 B (CE) (CBE) Solvus a + B 200 20 20 (Cu) 1200 1000 800 600 H 400 40 60 80 100 Composition (wt% Ag) (Ag) Temperature (F) The copper-silver phase diagram. [Adapted from Binary Alloy Phase Diagrams, 2nd edition, Vol. 1, T. B. Massalski (Editor-in-Chief), 1990. Reprinted by permission of ASM International, Materials Park, OH.]