The dislocation structures of polycrystalline specimens which had been crept for 196h at 580C were studied by means of transmission electron microscopy. It was found that the vast majority of the dislocations consisted of rectangular <110> dislocation loops which lay approximately on cube planes. The sides of the rectangles consisted of pure edge and pure screw dislocations. The edge sides were stepped, and one of them lay above the other, relative to the overall cube habit-plane. There were also figure-of-eight loops and single-turn helices. It was concluded that the operation of a double cross-slip mechanism that was based upon the cube planes explained the observations.

T.S.Rong, I.P.Jones, R.E.Smallman: Acta Metallurgica et Materialia, 1995, 43[8], 3085-92