Radiation-induced segregation and corrosion behavior on Sigma 3 coincidence site lattice and random grain boundaries in proton-irradiated type-316L austenitic stainless steel

摘要

The behavior of radiation-induced segregation (RIS) and intergranular corrosion at random grain boundaries and Sigma 3 coincidence site lattice (CSL) boundaries in proton-irradiated 316L stainless steel was examined. The frequency of the CSL boundaries was enhanced up to 86.6% by grain boundary engineering treatment prior to irradiation. Significant nickel enrichment and chromium depletion were induced at the random grain boundary owing to the RIS. At faceted Sigma 3 CSL boundaries, chromium depletion occurred at the asymmetrical boundary facet plane whereas no RIS was observed at the coherent twin boundary. After the electrochemical etching test, an intergranular corrosion groove was found along the random grain boundaries because of the low chromium concentration (similar to 12%) at the boundaries. At the faceted Sigma 3 CSL boundaries, the discontinuous groove along the asymmetric facet plane was completely disrupted by the non-corrosive coherent twin boundary. (C) 2012 Elsevier B.V. All rights reserved.