CONDENSED DISLOCATION IN POLYCRYSTALLINE ALUMINUM FATIGUED AT 77K

The authors have observed a type of dislocation structure which has not been reported before in any fatigued metal. It was not possible to determine whether the circular patches of dislocations correspond to spherical or cylindrical groupings. In either case the regular arrangement on a lattice suggests that a low energy dislocation configuration is formed in which a repulsive interaction between the clusters plays a role.