The trapping and release of He in model alloys of the Ni-Al system was studied, after post-bombardment annealing (920 to 1120K, up to 25h), by using thermodesorption spectrometry, internal friction and transmission electron microscopic techniques. The samples were bombarded with He+ ions, at room temperature, to a fluence of 5 x 1020/m2. It was shown that the amount of He which remained in Ni was considerably less than that in solid solutions after long-term post-bombardment annealing at 1020 or 1070K. Internal friction data showed that bombardment resulted in the formation of additional peaks in the internal friction spectra, which were not detected in the spectra of non-bombarded samples. It was suggested that more thermally stable complexes of HexMeyvx-type could form in substitutional solid solutions, in addition to the usual complexes of Hexvz-type in pure Ni.

Behavior of Ion-Implanted Helium and Structural Changes in Nickel-Base Alloys under Long-Time Exposure at Elevated Temperatures. I.I.Chernov, B.A.Kalin, A.N.Kalashnikov, V.M.Ananin: Journal of Nuclear Materials, 1999, 271-272, 333-9