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Problem 3: A circular edge dislocation loop on the (001) plane is shown in the figure below. The total elastic energy of such a loop is Eoy = 20 (", toop = 2R oy NGy Here R is the radius of this loop. We can ignore the dislocation core energy here. (a) Describe how the dislocation loop would change due to thermodynamic driving force if no external stress is applied. (b) Describe the type and direction of the applied stress that would be needed to hold the dislocation loop in equilibrium. (c) Write an expression for the magnitude of the applied stress needed to maintain equilibrium (Hint: you need first to calculate the dislocation line tension, which can be defined by as the derivate of the total dislocation line energy relative to the dislocation line length). (d) Determine if the equilibrium state produced by applying an appropriate stress as predicted in (c) is a stable equilibrium state (Hint: you need to analyze whether the force equilibrium can be reached under the same applied stress when there is a perturbation on the loop size). YV 1 [o10] X Il [100] Z 11[001]