a. Determine the diffusion coefficient for copper diffusing into aluminum at 300C. b. Create a plot showing diffusion coefficient vs. temperature for copper diffusing into aluminum over the range of 0C to 500C. Include a minimum of five data points (you may use Excel for the repetitive calculations). What does the shape of the curve tell you about the dependence of diffusion rate on temperature? Determine the diffusion coefficient for magnesium diffusing into aluminum at 300C. Explain why the value differs from that found for copper in Part a