Electrical Resistivity Study of Lattice Defects Introduced in Zone Refined-Iron by Deformation at -196°C

Recovery of zone refined iron deformed at -196°C was studied over the temperature range from -196° to 280°C by the measurements of electrical resistivity. The concentration of carbon and nitrogen contained in the iron was not more than 1 ppm. Eight stages of recovery were observed in the temperature range from -196° to 80°C. Three of them were predominant; the first stage is below -180°C with the activation energy of 0.15 eV and the order of reaction γ of 1.9, the second one around -160°C with the activation energy 0.2∼0.3 eV and γ of 4.2, and the third one around 50°C with the activation energy of 1.2 eV and γ of 3.1∼3.4. Then a continuous recovery followed above 80°C. It is concluded that the stage below -180°C was caused by the annihilation of di-interstitials and the stage around -160°C by the migration of single interstitials to dislocations. The stage around 50°C seems to be caused not only by interstitial impurities but also by deformation-produced defects, probably vacancies.