1. Which is easier for nucleation in solids, homogeneous or heterogeneous nucleation? What are the common defects present in solid solution (list at least five kinds of defects)? Are the defects generally harmful for nucleation and explain why?

2. The following figure shows the phase diagram and the corresponding homogeneous nucleation rates of composition X₀at different temperatures. T_eindicates the equilibrium temperature for ? and ? at X₀. Explain why the peak of nucleation rate happens at a temperature lower than T_e

Te T a Te - T T + 0 0 N N