Three typical interactions of persistent slip bands with different types of grain boundary were investigated and analyzed in fatigued Cu crystals. The results showed that persistent slip bands could not transfer through all types of large-angle grain boundaries, regardless of their orientation with respect to the stress axis. Secondary slip was often observed near the grain boundaries, leading to strain incompatibility. When the slip systems of the 2 adjacent crystals were co-planar, the transmission of a persistent slip band across a grain boundary depended strongly upon the slip directions of the 2 adjacent crystals. It was found that only the low-angle grain boundaries could pass through by persistent slip bands, and they were consequently insensitive to intergranular fatigue cracking. For a special Cu bicrystal with co-planar slip systems, the ladder-like dislocation arrangements within the adjacent persistent slip bands became discontinuous and a dislocation-affected-zone appeared near to the grain boundary due to the difference in slip direction of the 2 adjacent crystals. Therefore, the necessary conditions for the transmission of a persistent slip band across a grain boundary were that the neighboring grains had a co-planar slip system and identical slip directions.

What Types of Grain Boundaries Can be Passed through by Persistent Slip Bands? Z.F.Zhang, Z.G.Wang, J.Eckert: Journal of Materials Research, 2003, 18[5], 1031-4