(a) Draw schematic cooling curve for a copper-silver alloy (80wt% Cu-20 wt% Ag) from 1100 °C to 200 °C. 4. (b) What phases are present at 900 °C and what are their compositions and weight fractions? fru 20 7.S 40-7.5 10-20 90-7.S 7-61. (c) What is the weight fraction of the eutectic constituent in this alloy's microstructure at 750 °C? (d) What is the weight fraction of β precipitates in the primary α-phase at room temperature?