The solubility of carbon in high purity alpha iron measured by electrical resistivity at 4.2 K

The solubility of carbon in iron was studied using high purity (RRR approxi mate to 3000) alpha iron samples carbon-doped by levitation melting. Variou s methods of analysis were used and the results were compared to the target values. After quenching from 1000 K the obtained results show that the var iation of residual resistivity at 4.2 K as a function of the carbon concent ration in solid solution is nor monotonous. For carbon addition up to 50 ma ss ppm, the resistivity increment is 46.6 n Omega m/mol%, and for higher ca rbon addition the resistivity increment 31.4 n Omega m/mol%. The obtained r esults show that, for pure iron. carbon contents are low, at about one tent h of a ppm. The variations of carbon solubility in alpha iron, as determine d in this study, are close to those obtained by diffusion methods, but lowe r than those derermined by internal friction.