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5. (12 pts) A copper-silver alloy of composition 80 wt% Ag-20 wt% Cu is slowly cooled from a temperature of 1200 °C to 200 °C. The copper-silver phase diagram is shown below. (a) At 800 °C, what phases exit? What are their compositions? (b) At what temperature does the first Solid phase form? What is the composition of this Solid phase? (c) At what temperature does complete solidification occur? (d) At 779 °C, what phases exit? What are the compositions in these phases? (e) What is the composition of the last liquid remaining prior to complete solidification? (1) At 600 °C, what phases exit? What are the compositions in these phases? 20 40 60 80 100 1200 2200 0 2000 Liquidus 1000 Liquid -Solidus a +1 1800 F 1600 800 779 C (7) 00 B+L G B 8.0 (C. 1400 Temperature (°C) 71.9 (Cp) 91.2 (Cer Temperature (F) 1200 600 Solvus 1000 800 400 600 H 2000 20 40 60 80 400 100 (Cu) Composition (wt% Ag) (Ag)