In this paper we report on the electrodeposition of AuCu/B4C composites from acid baths with gold cyanocomplexes and no free cyanide. The electrochemical behaviour of the bath and the metallographic and crystalline structures of the electrodeposited alloys were studied with and without addition of particles. Electrochemical instabilities were previously observed for free-cyanide baths and their bearing on the structure of both pure matrix and composite electrodeposits were elucidated. No instabilities were observed in the alloy deposition from the acid baths containing complexed cyanide: compositionally and structurally homogeneous microstructures were obtained both with and without particle embedding.