Radiation-generated prismatic loops around gas bubbles in alumnium-lithium alloy

Abstract
Prismatic dislocation loops were observed to emanate from a gas bubble in neutron-irradiated aluminum-lithium alloy during electron irradiation at 200°C in a 200 kV electron microscope. The loops aligned in the 〈110〉 directions were analysed to be vacancy loops on 〈111〉 plane with a/2 〈110〉 Burgers vector. In a 1000 kV electron microscope, the prismatic punching were observed to occur during electron irradiation at 50°C. The prismatic loops were considered to nucleate at the surface of a gas bubble by condensation of radiation-produced vacancies and to propagate in the 〈110〉 directions by pencil glide under vacancy supersaturated environment.