A7: Grain boundary motion(Chapter 7) 13.5 points a) The velocities of a moving grain boundary in aluminium have been measured at different temperatures(see following table).The driving force during the experiment was kept constant.Determine from this data the temperature dependence of the grain boundary velocity v=f(T).Please represent the analysis in a graph and show your calculation steps with table.Calculate the activation energy (in eV).(7 points) v [um/s] 87 17,0 32,4 T [C] 400 415 430 b) Deduce the time law for discontinuous grain growth under the assumption that the average velocity of the grain boundary is proportional to the change of discontinuously growing grains'diameter over time.Explain the occurring variables. (4.5 points) c) The grain boundary motion can be hindered by foreign atoms.Sketch the dependency of velocity on the driving force in the case of a free moving boundary and in the case of a loaded boundary.Name a way,how to transfer the motion of a loaded boundary into a free moving boundary.(2 points)A7: Grain boundary motion (Chapter 7) 13.5 points a) The velocities of a moving grain boundary in aluminium have been measured at different temperatures (see following table). The driving force during the experiment was kept constant. Determine from this data the temperature dependence of the grain boundary velocity v = f(T). Please represent the analysis in a graph and show your calculation steps with table. Calculate the activation energy (in eV). (7 points) v [µm/s] 8,7 17,0 32,4 T [°C] 400 415 430 b) Deduce the time law for discontinuous grain growth under the assumption that the average velocity of the grain boundary is proportional to the change of discontinuously growing grains’ diameter over time. Explain the occurring variables. (4.5 points) c) The grain boundary motion can be hindered by foreign atoms. Sketch the dependency of velocity on the driving force in the case of a free moving boundary and in the case of a loaded boundary. Name a way, how to transfer the motion of a loaded boundary into a free moving boundary. (2 points)