Effect of copper and nickel on the neutron irradiation damage in iron alloys

Iron alloys containing copper and nickel were irradiated at 288°C to a fluence of 4.63 × 10¹⁹ neutrons/cm². Neutron irradiation produced defects which were observable by TEM in all of the iron alloys studied. The TEM analysis of the defects showed them to be interstitial dislocation loops with a 〈100〉 and a/2 〈111〉 Burgers vectors. The size, the number density, and the Burgers vector of dislocations were affected by the alloy composition. The addition of copper and nickel decreased the dislocation loop size and increased the fraction of a/2 〈111〉 loops. No voids or vacancy loops were observed in the irradiated iron alloys. The results are discussed in terms of dislocation loop nucleation and growth.