The growth of 9R stacked material at a Σ = 3 incoherent twin boundary was studied by means of  in situ  high-resolution transmission electron microscopy. Stacking defects which broke the normal, ABC BCA CAB ..., sequence of the 9R stacking were observed in the growing 9R layer. These faults were shown to arise from the presence of secondary grain boundary dislocations with Burgers vectors of a/6<¯211> type. It was shown that both the sense (positive or negative) and character (90º or 30º) of the grain boundary dislocation determined the characteristics of the 9R fault.

Stacking Defects in the 9R Phase at an Incoherent Twin Boundary in Copper D.L.Medlin, G.H.Campbell, C.B.Carter: Acta Materialia, 1998, 46[14], 5135-42