Calculate percentages solid and liquid, along with composition solid and liquid, using the lever rule for binary alloys with complete solid solubility.

A copper-nickel alloy containing 60 wt% copper is heated to 1,200°C, where it exists as a two-phase mixture of solid and liquid. The phase diagram shown indicates that at this temperature the solidus line intersects at 52 wt% Cu and the liquidus line intersects at 68 wt% Cu. What is the percentage of liquid phase present in the alloy at 1,200°C?

Refer to the phase diagram for the copper–nickel alloy system shown below. a) Determine the percentage of liquid phase present in a 65% nickel alloy at 1,280 °C. b) State the composition of the solid phase at this temperature.