Study of point defect behavior in V-Ti alloys using HVEM

Microstructural evolution and point defect behavior in vanadium, V-5Ti binary alloy and V-4Cr-4Ti alloy have been examined by using a high voltage electron microscope. In order to examine the effects of interstitial impurity atoms, V-Ti alloys with different levels of purity have also been examined. During irradiation, interstitial-type dislocation loops formed and grew in all of the materials. In alloys, the loop number density (CL) was much higher than that in vanadium. In high purity V-4Cr-4Ti, contrary to results from our previous study on vanadium, CL did not significantly decrease or change by purification, indicating solute atoms themselves strongly trap self-interstitial atoms (SIAs). From the temperature dependence of loop density in V-4Cr-4Ti, the effective migration energy of a SIA of 0.50 eVwas obtained. Various observed phenomena are discussed in terms of this activation energy. (C) 2002 Elsevier Science B.V. All rights reserved.