3hin films of CuAl alloys from pure Cu to pure Al were deposited by vacuum evaporation from single alloyed sources heated by electron bombardment. Information about the composition of the films obtained by electron microprobe was completed by lattice parameter measurements and structure information obtained by X-ray diffraction, as well as electrical resistivity measurements. The anticipated compositions of the films were calculated from the vapor pressures of the pure elements and thermodynamic data for liquid CuAl alloys at 1373 K. The agreement between the calculated values and the experimentally observed compositions is good only for alloys with low Al concentrations: less than 20 at.% Al in the source material. For the remainder of the CuAl system with more than 20 at.% Al in the source, the films were found to contain less Al than was calculated. This discrepancy might be due to too high values for the reported vapor pressures of Al. © 1977.