The behavior of vacancy-type dislocation loops under electron irradiation in iron

Two different types of dislocation loops were found in hydrogen ion implanted pure iron after annealing. The natures of these dislocation loops have been characterized by the inside–outside method of transmission electron microscope (TEM). It is found that the dislocation loops in specimens annealed at 670 K are interstitial type with b = 1/2〈1 1 1〉, n ≈ 〈1 1 2〉, and the dislocation loops in the specimens annealed at 770 K are vacancy type with b = 1/2〈1 1 1〉, n ≈ 〈0 1 1〉 or b = 〈1 0 0〉 and, n ≈ 〈1 1 2〉. Adding nickle element in iron could decrease the formation temperature of the vacancy loops.