Effect of dual-beam irradiation on the phase stability in low activation Fe-Cr-Mn alloys

In order to investigate the effects of helium on the phase stability and micro structural evolution in aged Fe-Cr-Mn alloy during modes of electron beam and electron/He+-ion dual-beam, in-site observation were carried out using a high voltage electron microscope connected with an ion accelerator, the effect of helium on the phases stability is appraised. Experimental results show that the low density of void were formed on the phase boundaries by electron irradiation only. The damage structure had synergistic effect during electron/He+-ion dual-beam irradiation. The change of phase stability were quickened. Example: radiation induced precipitate was grown due to diffusion of solute atom, new phase were formed which not formed in aging treatment alloys. The atomic mixing and the radiation disordering promote the modification of precipitated phases. The effect of interaction between helium and point defects and solute atom, and the change reason of phase stability were discussed. (authors)