The deformed state, dimensions and mosaicity of subgrains, arrangement and density of excess dislocations in Cu/Al coating deposited by mechanochemical technique are investigated by X-ray diffraction method. For Cu coating the estimates 10 nm, 6.4 x 10(11) cm(-2) and 0.24 GPa are evaluated for average size of subgrains, excess dislocation density and shear strength, respectively. The strain-hardening mechanism of constraint on dislocation motion is proposed to be a dominant channel for the coating strengthening. A model is proposed for interdiffusion process of the Cu and the Al atoms at the Cu/Al interface. It is assumed that this interdiffusion is activated by the impact temperature oscillations due to repeated "ball-coating" collisions over the deposition process. On the basis of analysis of X-ray diffraction data and the obtained estimate for diffusive run of the Cu atoms into the Al substrate, formation of a Al1-xCux transition layer with compound parameter x approximate to 0.02 and thickness 5.1 mum is predicted. (C) 2003 Published by Elsevier B.V.