Directional recrystallisation in nicl<el based high tel11perature alloy

The directional recrystallisation during zone annealing of a nickel alloy intended for high temperature use has been investigated. The material was processed from powder, by extrusion and rolling, to produce sheet. Zone annealing of that material led to a very coarse, directional grain structure with a distinctly different preferred orientation to that of the rolled and primary recrystallised material. There was no correlation between the preferred orientations of the large grains and their growth directions. The textures were related by a transformation close to that characteristic of a I5 coincident site lattice. It is possible that this represents a rapid growth relationship in the case where the growth is controlled by the dissolution of the coherent y' precipitate. MST/3436