1. Draw a schematic figure and explain the grain growth velocity as a function of grain size from 0.01 to 100μm for a single-phase system with high solute segregation at the grain boundary. Assume normal grain growth at any grain size.
2. Consider a solid solution containing two kinds of solutes with very fast and very slow diffusivities perpendicular to the grain boundary. Assuming a high solute segregation at the grain boundary and the same interaction potential of the grain boundary for the two kinds of solutes, draw schematically and explain the variation of solute drag force with grain size.