Concept explainers
The flux of carbon atoms between the surface and plane
Answer to Problem 34SEP
The flux of carbon atoms between the surface and plane
Explanation of Solution
It is given that the 1018 steel having
The number of carbon
The number of iron
The atom % of carbon is expressed as follows.
Thus, the concentration of carbon surface is
Write the formula for lattice constant
Here, the radius of the iron atom is
Write the formula for volume
Write the formula for Fick’s law of diffusion.
Here, flux or flow of atoms is
Conclusion:
Refer Table 3.2, “Selected metals that have the BCC crystal structure at room temperature (20°C) and their lattice constants and atomic radii”.
The atomic radius of iron is
Substitute
Substitute
The number of atoms per unit volume is expressed as follows.
The concentration of atoms at the surface
The concentration of atom at the distance of
Refer Table 5.2, “Diffusivities at 500°C and 1000°C for selected solute-solvent diffusion systems”.
The diffusivity of carbon in FCC iron at 1000°C is
Here,
Substitute
Thus, the flux of carbon atoms between the surface and plane
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Chapter 5 Solutions
Foundations of Materials Science and Engineering
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