(b) Discuss why the strain hardening exponent decreascs with increasing stacking fault energy, as shown in the table below (5%)

(d) In fec metals, the dislocations are usually dissociated into an extended dislocation, containing two partial dislocations and a stacking fault. Fig. 2 shows an extended dislocation in fcc lattice. Describe the position of the partial dislocation including the direction of dislocation line and Burgers vectors. (5%)