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

Abstract 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 ( C L ) was much higher than that in vanadium. In high purity V–4Cr–4Ti, contrary to results from our previous study on vanadium, C L 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.