Material science

Question 12 1 pts Compare diffusion coefficients for the interdiffusion of carbon in both a-iron (BCC) and 7-iron (FCC) at 950C. Which one has higher diffusion coefficient? Assume that Do for the interdiffusion of carbon in a-iron (BCC) and in 7-iron (FCC) are 1.1 x 10- 6 and 2.3 x 10-5 m2/s, respectively, and that Qd are 87.4 and 148 kJ/mol, respectively. Not enough information to make this comparison. Neither. They are approximately the same. The a-iron (BCC) is higher. The y-iron (FCC) is higher. Question 13 1 pts An FCC iron-carbon alloy initially containing 0.15 wt% C is carburized at an elevated temperature and in an atmosphere wherein the surface carbon concentration is maintained at 1.0 wt% C. If after 49.5 h the concentration of carbon is 0.35 wt% C at a position 4.0 mm below the surface, determine the temperature in degree Celsius (C) at which the treatment was carried out. 1053 C 816 C 982 C 779 C 945 C 708 C