The Influence of the Isotopic Composition Of the Hydrogen Component in Vanadium-Hydrogen Alloys upon the Ion-Irradiation-Induced Segregation of Hydrogen

The interaction of radiation-induced defects with deuterium atoms at room tenperature was studied for commercial vanadium, V-H and V-D alloys. During a 700 keV D⁺ bombardment the accumulation of D in the irradiated area was measured by means of NRA using the reaction D(d,p)T. It was shown that in the irradiated area of the V-D alloys (0.01–0.1 at .% D) the D concentration depends on both the fluence and the alloy composition. As the fluence is increased, the accumulated amount saturates. The saturation level depends on the D concentration and is 3 to 6 times as high as the D concentration in the bulk. The D segregation is due to the formation of immobile or low-mobile “D atom — radiation defect” conplexes. At the same time free D atoms are almost immediately redistributed in the bulk of the sample. A complex deuterium-protium segregation in V-D and V-H alloys under D⁺ bombardment was studied too. The accumulation of implanted deuterium in the irradiation-damaged area was examined for alloys with a high (0.6–2.65 at .% H) content of ¹H hydrogen isotope. It is shown that the implant accumulation level is indepedent of the bombardment dose but is determined by the content of “free” protium in the alloys: the higher the protium concentration, the lower the accumulation level.