2. Using the Cu-Zn phase diagrams in the lecture three notes, for an alloy composition of 74 wt% Zn-26 wt% Cu, cite the phases present and their compositions at the following temperature: a. 850C b. 750C c. 680C d. 600C e. 500C 3. For the phases of the alloy and temperatures given in Problem 2, determine: a. The relative phase amounts for (a)-(e) in mass fraction. b. Convert mass fraction to volume fraction for the phases present at 500C (parte). c. From a practical standpoint, why would one want to know relative phase amounts in volume fraction vs. mass fraction