Study of Defects Introduced by 2 and 9 MeV Electron Irradiation in B2 Type Fe-Al Alloy

It is well known that intermetallic compound alloys possibly include more than two types of vacancies basically, that is A-vacancy and B-vacancy in A-B compound alloy. Although MeV ordered electron irradiation produces vacancies and interstitials, the threshold energy of displacement for each elemental atom in intermetallic alloys is not necessarily same. Then the defect type introduced by the irradiation depends on electron energy. In this study, we performed positron annihilation lifetime and Doppler broadening measurements for different energy of electron irradiated B2 type Fe50%Al alloy. The values of positron annihilation lifetime for this alloy after 2 and 9 MeV electron irradiation were 200 and 172 psec, respectively. Also, the Doppler broadening parameters S and W show difference for this alloy with different energy of electron irradiation. These results suggest that different types of vacancy were induced into Fe-Al compound alloy by electron irradiation with different energies.