In situ observation of glide motions of SIA-type loops in vanadium and V–5Ti under HVEM irradiation

In situ observation of one-dimensional glide motion of defect clusters under HVEM irradiation has been conducted. In order to examine the effects of interstitial impurity atoms and alloying elements, vanadium, in two purity levels, and V–5Ti have been prepared and examined. In all materials, self-interstitial type dislocation loops are formed and grow during irradiation. Loop glide was frequently observed under conditions of extremely high irradiation intensity. Motion was more frequently observed when clusters were small, and generally, decreased as clusters grew. All clusters glide one-dimensionally, back and forth between other neighboring loops, indicating the driving force for motion is the variation of the force field gradient around loops. The frequency and distance of motion are significantly decreased by interstitial impurities and solutes in the material. The dynamical characteristics of one-dimensional motion under HVEM irradiation are discussed. It can be concluded that impacts of one-dimensional motion in practical alloys are less important than those in pure metals.