FATIGUE-INDUCED DISLOCATION-STRUCTURE OF TITANIUM-ALLOY VT5-1CT AT TEMPERATURES OF 293-11-K

The dislocation structure formed during the final stage of fatigue at high- and low-amplitude stresses at T = 293 K in air and T = 293, 93 a nd 11 K in high vacuum is studied on the Ti alloy VT5-1ct which has be en prepared by two processing methods. The sigma-N curves are plotted for corresponding experimental conditions. It is shown that slip alone is responsible for the plastic deformation. The characteristic featur es of the dislocation structure formed are reported. The morphology of the alpha phase does not influence the character of the dislocation s tructure. At lower temperatures, the substructure remains practically unaltered, although the likelihood of uniformly distributed dislocatio ns is lower. The lifetime is essentially dependent on the environment, temperature and the alloy microstructure, the latter being especially important at low temperatures in the high-amplitude region.