β Scribed by P. Charsley; U. Bangert; L.J. Appleby
No coin nor oath required. For personal study only.
Pure polycrysmlline aluminium specimens have been cyclically deformed at total strain amplitudes in the range 2 x 10 -4 to 1.4 x I0 -.~ at temperatures of 77 K, 163 K and 223 K. Transmission electron microscopy studies of dislocation configurations have been made. Wall structures including persistent slip band ladder-type structures" have been observed within limited ranges of temperature and amplitude. It has been found that wall structures are relatively unstable at higher temperatures. Significant differences in detail are found in comparison with copper in particular. For particular configurations a larger number of Burgers" vectors" are observed compared with polycrystalline copper. This" results in differences in the homologous temperature ranges within which particular configurations are observed, when comparing aluminium with copper, and it is suggested that this aris'es mainly because of differences" in the stacking fault energy, which determines the stress required for dislocation intersection.
π SIMILAR VOLUMES
Knowledge about the fatigue behaviour of metallic materials in the range of very high cycle fatigue (VHCF, N > 10 7 ) is a key factor to improve the safety against failure of component parts. Even in the conventional field of application of nickel-base alloys (e.g. turbine blades) superimposed high