1. The Phase Diagram Problems

2. 1.2. Determine the liquidus temperature, solidus temperature, and freezing range, then determine the phases present, the composition of each phase, and the amount of each phase in mol% at 2400 o C for the following NiO-MgO ceramic compositions: a.NiO-30 mol% MgO b.NiO-45 mol% MgO c.NiO-85 mol% MgO 1.1. A NiO-60 mol% MgO is allowed to solidify. Determine a.The composition of first solid to form and b.The composition of the last liquid to solidify under equilibrium conditions

4. 4. A NiO-20 mol% MgO ceramic is heated to 2200 o C. Determine: a.The composition of the solid and liquid phases in both mol% and wt% and b.The amount of each phase in both mol% and wt% c.Assuming that the density of the solid is 6.32 g/cm 3 and that of the liquid is 7.14 g/cm 3, determine the amount of each phase in vol%. 2. How many grams of MgO must be added to 1 kg of NiO to produce a ceramic that has a solidus temperature of 2200 o C? 3. How many grams of MgO must be added to 1 kg of NiO to produce a ceramic that contains 25 mol% solid at 2400 o C?

5. 5. How many grams of Ni must be added to 500 g of Cu to produce an alloy that has a liquidus temperature of 1350 o C? What is the ratio of the number of Ni atoms to Cu atoms in this alloy? 6. How many grams of Ni must be added to 500 g of Cu to produce an alloy that contains 50wt%  at 1300 o C? 7. Suppose a crucible made of pure Ni is used to contain 500 g of liquid Cu at 1150 o C. Describe what happens to the system as it is held at this temperature for several hours. Explain.

6. 8. Consider a Pb-70% Sn alloy. Determine: a.If the alloy hypoeutectic or hypereutectic, b.The composition of the first solid to form during solidification, c.The amounts and compositions of each phase at 184 o C, at 25 o C. 9. A Pb-Sn alloy contains 45%  and 55%  at 100 o C. Determine the composition of the alloy. Is the alloy hypoeutectic or hypereutectic? 10. Calculate the total amount of  and  and the amount of each microconstituent in a Pb-50% Sn alloy at 182 o C. What fraction of the total  in the alloy is contained in the eutectic microconstituent? Microconstituent: a phase or mixture of phases in an alloy that has a distinct appearance. Frequently, we describe a microstructure in terms of the microconstituents rather than the actual phases.