Observation and analysis of defect structure evolution from radiation damage by D-T fusion neutrons

Abstract

A previous report on the defect structure evolution in metals, alloys and other materials by D-T fusion neutron irradiation (J. Nucl. Mater. 133&134 (1985) 85) was not accompanied with figures and illustrations, and they are all presented in this paper. More than half of the figures consists of electron micrographs, including the following: disordered zones to show the flight distances of interstitial atoms, amorphous zones in a semiconductor, grouped defect clusters developed from sub-cascade damage, stereo-micrographs of three dimensional configurations of defect clusters in sub-cascade groups, variation of defect structures with irradiation temperature, comparison of defect structures developed in thin foil and bulk specimens to demonstrate the role of free interstitials, homogeneous and localized formation of interstitial clustered defects, detection of invisible defects by the aid of electron illumination, and dislocation structures introduced by the deformation of irradiated materials. The other figures contain numerical results of micrograph analysis, which can be used for the estimation of neutron collision cross-section and primary knock-on energy. Point defect processes occurring during the damage structure evolution, including the dynamical effect of collisions, are discussed on the basis of experimental observations.