The $Al-Cu$ binary, equilibrium phase diagram is attached. For a $4\mathrm{.}5\%Cu-Al$ alloy

determine: $$

a$)$ Which phases are present at room temperature?

b$)$ How much of each phase is present?

c$)$ What is the composition of each phase?

d$)$ If an age hardening heat treatment were applied, determine how many $$

precipitates would form if the radius was $10$ nm vs $100$ nm $.$ Assume $$

density $=4\mathrm{.}5\frac{g}{c}c.$

e$)$ On the basis of a $1$ mm $2$ area, what would be the corresponding

increase in shear strength for a $10$ nm precipitate vs a $100$ nm precipitate?