Four types of V-4Cr-4Ti alloy, with various O and N contents, were irradiated with Cu2+ ions to a dose of 10dpa at 973K. Under these irradiation conditions, the O-flux through the surface was estimated to be about 3 x 10-16/m2s, and the O levels in specimens were calculated by means of finite difference method. In the case of high-purity specimens, O diffused from the surface and into the irradiated region. The O also diffused from the back of the irradiated surface and into the irradiated region, and enhanced precipitations in the irradiated region. It was shown that the initial impurity level and flux of O, which diffused from the atmosphere, essentially limited the precipitation behaviour.

The Diffusion Behaviors of Interstitial Impurities in V-4Cr-4Ti Alloys under Ion Irradiation. M.Hatakeyama, S.Tamura, T.Muroga, N.Yoshida, M.Hasegawa, H.Matsui: Journal of Nuclear Materials, 2007, 367-370[1], 882-6