A full dislocation often dissociates into two partial dislocations enclosing a stacking fault ribbon. The stacking-fault width significantly affects the mechanical behavior of metals. Al has very high stacking-fault energy and, consequently, very narrow stacking-fault width in its coarse-grained state. It was found that some stacking faults in nanocrystalline Al were surprisingly wide (1.4 to 6.8nm), which was 1.5 to 11 times higher than the reported experimental value in single crystal Al. The analytical model showed that such wide stacking faults were formed due to the small grain size and possibly also to the interaction of stacking faults ribbons with a high density of dislocations.

Formation Mechanism of Wide Stacking Faults in Nanocrystalline Al. X.Z.Liao, S.G.Srinivasan, Y.H.Zhao, M.I.Baskes, Y.T.Zhu, F.Zhou, E.J.Lavernia, H.F.Xu: Applied Physics Letters, 2004, 84[18], 3564-6