(Solved): 1. Explain the differences in the microstructures (i.e., defect/dislocation and grain structure) f ...

1. Explain the differences in the microstructures (i.e., defect/dislocation and grain structure) for a metal that has been cold rolled, one that has been cold rolled and then recovered, one that has been cold rolled and then recrystallized, and one that has been cold rolled, recrystallized with the grains then allowed to grow. (10 pts) 2. A hypothetical metal alloy has a grain diameter of \( 8.0 \mu \mathrm{m} \). After a heat treatment at \( 430^{\circ} \mathrm{C} \) for \( 120 \mathrm{~min} \), the grain diameter has increased to \( 40 \mu \mathrm{m} \). Compute the time required for the specimen of the same original material to achieve a grain diameter of \( 60 \mu \mathrm{m} \) by heat treating at \( 430^{\circ} \mathrm{C} \). Assume the grain diameter exponent \( (\mathrm{n}) \) has a value of \( 2.1 .(10 \mathrm{pts}) \)