Deformation-corrosion interactions for Zr alloys during I-SCC crack initiation - Part II: Localised stress and strain contributions

For a better understanding of the initiation step of iodine induced stress corrosion cracking (SCC) in Zr alloys, responsible for pellet-cladding inte raction (PCI) fuel rod failures, an analytical study has been undertaken, t he aim of which being focused on the respective roles of local chemistry an d stress/strain state on the crack nucleation. This second part is mostly r elated to the local stress induced by strain incompatibilities between grai ns. Using EBSP (electron back-scattering pattern) to analyze the crystallog raphic orientation of all the grains of the samples tested in SCC, it was p ossible to conclude that the major parameter controlling the nucleation of the intergranular cracks is not related to grain to grain strain incompatib ilities, but to the orientation of the grain boundary planes with respect t o the tensile stress. (C) 1999 Elsevier Science B.V. All rights reserved.