7- The following plot shows the diffusion coefficients of Fe in a-iron (BCC) and C in y-iron (FCC) and C in u-iron (BCC). a- Explain why at 1000 K: (2 pts) i- the diffusion coefficients of C in a-iron > C in y-iron, Temperature (C) 600 500 400 300 1500 1200 1000 800 101 30-10 Cinyre Cine 10-12 ii-the diffusion coefficients of C in a-iron > Fe in a-iron, Diffusion coefficient is! 10- 30-16 Fine b. Determine the diffusion activation energy and pre- exponential for C in a iron (3 pts) - 100 05 2.0 1.0 1.5 Reciprocal temperature (1000)