Deformation of polycrystalline samples, above the brittle-ductile transition temperature, was considered. Samples were deformed at 1200, 1400 or 1600C, using strain rates ranging from 10-5 to 10-2/s. Thin foils were cut from deformed samples, and diffraction contrast methods were used to determine the identities of dislocations in the deformed microstructure. Crystallographic analyses of the line direction of defects, and knowledge concerning the Burgers vectors, were combined so as to assess the degree to which slip and climb occurred during deformation. It was concluded that glide occurred, during deformation at 1200C, at all strain rates. However, there appeared to be an increasing contribution from climb, at 1400C, as the strain rate was reduced. At 1600C, climb appeared to be the predominant deformation mechanism at all strain rates.

D.J.Evans, F.J.Scheltens, J.B.Woodhouse, H.L.Fraser: Philosophical Magazine A, 1997, 75[1], 1-15