B、 Questions:
1. Question for Classical Nucleation (10%)
The free-energy vs. composition curves at 700 °C for an A-B binary alloy are shown in Fig.
1. Consider the two alloys of A-70 and A-80% B. The precipitates were spherical and
coherent to nucleate at 700 °C. Ignoring the coherency-strain effect, and assuming the
interfacial free energy ($\gamma$ = 200 erg/cm²) for both nuclei with their equilibrium
compositions, determine the ratio of A atoms in $\alpha$ nuclei of critical size (i.e.,
n*A-70B/n*A-80B)