Above is the Cu-Ni phase diagram like the one shown in the lecture, be careful that this diagram is in atomic percentage. The (Cu, Ni) phase is a crystalline solid with an fee unit cell. The right side of the x-axis is 100% Ni, and the left side of the x-axis is 100% Copper. What phase(s) is the Cu_30Ni_70 material in at 1200 degree C? What phase(s) is the Cu_50Ni_50 material at 1250 degree C? The Cu_70Ni_30 alloy is in a Liquid + solid mixture at 1200 degree C. At this composition and temperature, what is the composition of the liquid phase, and what is the composition of the fee solid?