Question

estimate approximately the atomic per cent of interstitial carbon required to fill all the core sites of edge dislocation in iron.assume the edge dislocation density to be 10^11m^-2

Answer 1

The size of a carbon atom is 170 pm, the diameter of an iron atom is 126 pm. Since atoms of carbon are "fixed" near atoms of iron, the percent of interstitial carbon is

$$\epsilon=\frac{170}{170+126}\cdot100\%=57\%.$$