$4-$ For a copper $-$ silver alloy of composition $\backslash (65\backslash$mathrm$\{$wt$\}\backslash \%\backslash$mathrm$\{$Cu$\}-35\backslash$mathrm$\{$wt$\}\backslash \%\backslash$mathrm$\{$Ag$\}\backslash )($Figure $3)$ do the following:

a$)$ What is the primary phase?

b$)$ Is this alloy hypoeutectic or hypereutectic?

c$)$ Determine the freezing rang and freezing interval of this alloy.

d$)$ Determine the mass fractions and composition of the phases present at $\backslash (780^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$

e$)$ Determine the mass fractions and composition of the phases present at $\backslash (700^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$

f$)$ Draw a schematic cooling curve for this alloy.

g$)$ Sketch the microstructure changes during solidification for this alloy.

Fi ;

$2$