- #1
MightyQuinn
- 4
- 0
Hello experts in diffusion,
I am having some trouble understanding some concepts in calculating diffusion. First, I understand activity (or chemical potential) drives diffusion, but where does this come into play in the calculations? Is it in the activation energy (Q) in the Arrhenius equation (D=Doexp(-Q/RT))?
Next, where can I find data online for Do and Q for materials like 4340 steel etc? Or would I just use values for Carbon in FCC (Fe) if my temperature is austenitizing? I have found some values online which do not compare at all, so I assume they are wrong!
My reason is that I want to show in calculations that a steel say 4340 (with ~no Si content) will not carburize as much as a similar steel with ~3% Si or greater. How can I show this in calculations? Its obvious that it is because of the chemical potential gradient driving C away from the Si, but how can this be shown mathimatically. I have a good bit of literature and have done several searches and I cannot not find anything explaining this very important problem.
Any help is greatly appreciated
I am having some trouble understanding some concepts in calculating diffusion. First, I understand activity (or chemical potential) drives diffusion, but where does this come into play in the calculations? Is it in the activation energy (Q) in the Arrhenius equation (D=Doexp(-Q/RT))?
Next, where can I find data online for Do and Q for materials like 4340 steel etc? Or would I just use values for Carbon in FCC (Fe) if my temperature is austenitizing? I have found some values online which do not compare at all, so I assume they are wrong!
My reason is that I want to show in calculations that a steel say 4340 (with ~no Si content) will not carburize as much as a similar steel with ~3% Si or greater. How can I show this in calculations? Its obvious that it is because of the chemical potential gradient driving C away from the Si, but how can this be shown mathimatically. I have a good bit of literature and have done several searches and I cannot not find anything explaining this very important problem.
Any help is greatly appreciated