A natural, in-situ, metal-matrix composite Al-Nb with an intermetallic phase Al3Nb with a fraction of 25% at. was obtained by deformation shear under pressure and subsequent annealing. The microstructure of the composite was studied. The emission efficiency in the glow discharge of Al-Nb composite, as well as aluminum and niobium as cold cathodes, was determined. The analysis of the difference between the glow discharge current at fixed voltages for cathodes from the studied materials is carried out.