Study of grain boundary character along intergranular stress corrosion crack paths in austenitic alloys

Samples of austenitic stainless alloys were examined by means of scanning and transmission electron microscopy. Misorientations were measured by electron backscattered diffraction. Grain boundary distributions were analyzed with special emphasis on the grain boundary character along intergranular stress corrosion cracks and at crack arrest points. It was established that only coherent twin Σ3 boundaries could be considered as “special” ones with regard to crack resistance. However, it is possible that twin interactions with random grain boundaries may inhibit crack propagation. The results suggest that other factors besides geometrical ones play an important role in the intergranular stress corrosion cracking of commercial alloys.