TiW films, prepared by magnetron sputtering of highly pure cast tungsten and titanium, were studied. Auger electron spectroscopy (AES) data showed that the Ti/W ratio in the TiW films was nearly constant during the sputtering lifetime of the composite targets. The TiW films were solid solutions of titanium in a tungsten matrix with increased tungsten lattice parameters. It was shown that the relative increase in the tungsten lattice parameters depended on the condition of the silicon substrate or sublayers on which the films were deposited. The TiW layers influenced the preparation conditions of the nucleation and growth of aluminium films, which were characterized by a highly dispersed microstructure.