Calculate in Excel using VBA.

The diffusivity is a measure of how fast diffusion occurs and can modeled as D=D_oexp(-Q/RT) , name this Sub divs, where

D= diffusivity, cm²/s

D_o= diffusion coefficient, cm²/s

Q= activation energy, J/mol, 8.314J/mol K

R= ideal gas constant, J/mol K

T= temperature, K

As iron is heated, it changes structure and its diffusion characteristics change. The values of D_o and Q are shown in the following table for carbon diffusing through each of iron's structures:

Types of metal	Do (cm2/s)	Q (J/mol K)
alpha Fe (BCC)	0.0062	80,000
gamma Fe (FCC)	0.23	148,000

Create a plot of diffusivity versus inverse temperature (1/T), using the data provided. Try the rectangular to see if it represents the best results. Let the temperature vary from room temperature (25^oc) to 1200^oc in increments of 100. Make a table temperature table of c^o and K and convert the celsius to Kelvins in the VBA macro. In the main maro, call divs(alpha) then call divs(gamma).