Effect of Doping on Helium Behavior and Bubble Structure Development in Nickel and Vanadium Alloys

Transmission electron microscopy and thermal desorption spectrometry are used to study the behavior of ion-implanted helium and formation of a gas bubble structure in fcc and bcc metals as a function of the concentration of the alloying elements (aluminum in nickel and titanium in vanadium). It is shown that during post-radiation annealing of room-temperature irradiated samples alloying in both types of alloys substantially decreases the size and increases the density of the bubbles formed. In nickel–aluminum alloys, with post-radiation uniform heating, the thermal desorption peaks shift to high temperature with increasing aluminum content and, conversely, in vanadium–titanium alloys a shift to low temperature with increasing titanium concentration occurs, though the effective gas release activation energy increases in both alloys with increasing concentration of the alloying element. The data obtained are discussed from the standpoint of the influence of doping on the mechanisms of growth and migration of bubbles.