Portal de Periódicos da CAPES

Vacancy formation energy in iron by positron annihilation

1978; IOP Publishing; Volume: 8; Issue: 5 Linguagem: Inglês

10.1088/0305-4608/8/5/001

1747-3918

S M Kim, W. J. L. Buyers,

Fusion materials and technologies

The temperature dependence of the positron annihilation peak coincidence rate has been measured in iron from 20 degrees C to 1320 degrees C. The peak rate did not change across the ferro-para magnetic transition at approximately 770 degrees C but decreases by 1.5% across the alpha - gamma phase transition at 910 degrees C. The trapping model analysis of the data yields values of the vacancy formation energies (Ef) of 1.4+or-0.1 eV in alpha -Fe and 1.7+or-0.2 eV in gamma -Fe. The correlation between Ef and Tt, where Tt is the threshold temperature, has been derived from the trapping model.