Initial dislocation density of a FCC single crystal is 10 m/m'. The yield strength of the crystal is 3.675 MPa when the tensile load applied along the [0 0 1] direction. (a) Find out the critical resolved shear stress (CRSS) of the crystal. (b) If the dislocation density increased to 10 m/m after 30 % elongation, calculate the magnitude of applied tensile stress (along [001] direction) necessary to initiate yielding. The base stress to move the dislocation in the crystal in the absence of other dislocations is 0.5 MPa. [5+5]