The microstructure damage behavior of aging treatment low activation Fe-Cr-Mn(W, V) alloys irradiated by electron/helium dual-beam

The effect of helium on irradiation damage behavior in aging treated low activation Fe-Cr-Mn(W,V) steel was investigated by electron/helium ion dual-beam irradiation. The results indicate that when the single electron irradiation dose was over 10 a-1, lower density voids formation was recognized in 923 K/3000 h aged specimens. The interstitial type dislocation loop and small void were formed in the early stage in aged specimens under dual-beam irradiation. With increasing aged temperature the mean size and density of voids became larger and void swelling of aged specimens was much higher than that of no-aged ones by dual-beam irradiation. The irradiation-induced grain boundary segregation of Cr and Mn elements were effectively suppressed by the helium. With increasing aged temperature the carbide precipitates increased in number, but the amount of additional elements, such as Mn, W and V decreased in the solution matrix, The results also indicate that the decrease of solution elements in the austenitic more effectively promoted the void swelling by dual-beam irradiation. (authors)