Using scanning and transmission electron microscopy, the analysis of the structure, phase and elemental composition of the contact zone of the system coating (high-entropy FeCrCoNiMn alloy)-substrate (5083 alloy) after electron-beam processing was performed. The formation of a multiphase, multielement submicro- and nanocrystalline structure has been established. The structure of high-speed cellular crystallization in the contact layers adjacent to the coating and substrate is revealed, and the formation of lamellar crystals in the central region of the contact zone is also found. Keywords: contact zone, high-entropy alloy, wire-arc additive manufacturing method, 5083 aluminum alloy, pulsed electron beam, elemental and phase composition, structure.