Dependence of Void Formation on Phase Stability in Neutron Irradiated Type 316 Stainless Steel

摘要

The void swelling rate in Type 316 stainless steel is dominated by the instantaneous composition of the austenite matrix rather than by the concurrent nature of the dislocation and void microstructure alone. This is the conclusion derived from a series of neutron irradiation experiments designed to determine which microstructural components account for the variability of void development observed in this alloy in response to changes in composition, preirradiation treatment and irradiation history. The attainment of steady-state swelling is thought to be related to the development of a saturation microstructure of precipitates and dislocations. The existence of a saturation state for dislocation microstructure has been confirmed, but this condition is reached at fluences substantially below the onset of steady-state swelling. Relative to a solution-annealed treatment, 20% cold working accelerates the approach to saturation of the dislocation microstructure; thus the delay of swelling by cold work cannot be rationalized simply in terms of the time or fluence dependence of dislocation density. (ERA citation 04:027218)