EFFECT OF HYDROSTATIC PRESSURE ON THE DISLOCATION STRUCTURE AND DEVELOPMENT OF FRACTURE IN DEFORMED ALUMINIUM.

The experiments were performed on specimens of polycrystalline aluminium (99. 97%). The conclusion that pressure does not essentially influence the elements of dislocation structure is supported by data on the annealing of work-hardened aluminium under atmospheric and high (5000 atm) pressures. The specimens were annealed for an hour at 300 degree C. It was found that the dislocation density calculated on the basis of cell misalignment was substantially reduced after annealing (approximately halved), but did not depend on the pressure applied during annealing. The strengthening of aluminium observed under pressure is due to the influence it exerts in moderating the development of fracture in the specimens under deformation.