Slip bands (SBs) are extensively observed in metallic polycrystals subjected to various loading conditions (tensile deformation, fatigue, SCC, post-irradiation tensile loading). SB impingement toward grain boundaries (GBs) seem to trigger GB fracture. Since the fifties, the pile-up theory has been extensively used for predicting both GB stress fields and fracture. Nevertheless, depending on material, temperature and loading conditions, the SB thickness ranges between 50nm and a few microns. Then, plastic slip is much more homogeneously distributed than in pile-ups. Extensive FE crystal plasticity computations accounting for grain size, SB thickness, load... are carried out. The results show that the pile-up theory largely overestimates GB stress fields. The application of finite crack fracture mechanics provides predictions in much better agreement with experiments than the pile-up ones. Close-form expressions are deduced from the numerous FE computation results.
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