Self-oscillation processes during the structure relaxation of palladium-metal alloys (Pd--W) saturated with hydrogen

Some possibilities of studying real microscopic structures by X-ray kinetic techniques are considered. Taking variable-composition Pd—W alloys as examples, a comparative time dependence analysis of the X-ray diffraction pattern (i.e., of the intensity and width of diffraction maxima) is carried out for palladium—metal alloys relaxing after hydrogen saturation. It is shown that the dependences are of nonmonotonic — at some relaxation stages, of oscillatory — character. Analysis indicates that these dependences are due to the self-organisation effect operating during the diffusion evolution of an alloy structure having submicroscopic heterogeneity. The self-organisation mechanisms most likely for a system of local short-range order regions, hydrogen-containing clusters, defects, and hydrogen atoms are considered. Classes of materials allowing such phenomena are discussed.