Factors which control the swelling of FeCrNi ternary austenitic alloys

Abstract

In agreement with limited earlier studies, a comprehensive irradiation experiment conducted in both EBR-II and FFTF demonstrates that while cold-working usually decreases void swelling of ternary FeCrNi alloys at relatively low irradiation temperatures, it in general increases swelling at higher irradiation temperatures. Aging of cold-worked specimens to produce cellular dislocation networks tends to further increase swelling, especially at higher nickel levels. The swelling of ternary alloy at lower nickel levels also appears to be sensitive to details of the preirradiation annealing treatment. The differences in the details of reactor operating conditions also exert an influence on void nucleation and thereby on the duration of the transient regime of swelling. In the current irradiation series this leads to the swelling developed in EBR-II at ∼ 30 dpa being consistently larger than that in FFTF. All of these results confirm an earlier conclusion that the primary variability of void swelling of FeCrNi alloys lies in the incubation and transient regimes, rather than in the steady-state swelling rate regime. Under certain conditions, the transient regime can be made to approach 0 dpa.