The results of Х-ray research on the structural characteristics of the Pd$_3$Ni alloy after its electrolytic saturation by hydrogen during relaxation are presented. The synchronous changes in the period of a lattice and the value of elastic stresses, which started immidiately after sample hydrogenation and continued for 500 hours of relaxation, were found for the first time. The observed changes are caused by the cooperative processes of the displacements of vacancies and nickel atoms between defect complexes and an alloy matrix.
64.00.00 Equations of state, phase equilibria, and phase transitions
61.00.00 Structure of solids and liquids; crystallography
61.10.-i X-ray diffraction and scattering
Department of Physics, Moscow State University, Moscow, 119991 Russia