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The nature of short‐range ordering (SRO) in solid solutions of Cu, Ag, and Fe with aluminium is studied by X‐ray scattering. The characteristics of SRO are found to depend on concentration and temperature. The structure of the SRO corresponds, in the ideal case, to superstructures or phases which exist in the same alloys at higher Al concentrations.

A general solution of the problem of multiple scattering on a localized random potential is achieved in a single-band model of diagonal disorder for a binary substitutional alloy. A configurationally averaged (T)-matrix is presented as a cluster-type expansion. The short-range order effect on the electronic spectrum, specific heat capacity, and residual electrical conductivity is studied with regard to the multiple scattering on a two-particle cluster (on pairs of atoms) for the coherent potential satisfying the condition of the single-site approximation. Expressions for the electronic density of states and electrical conductivity (allowing for the scattering on pairs) are presented in an analytical form.

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Concentration dependences of the electronic density of states near the Fermi level and the Cowley short-range order parameters are presented for the Ag-A1 solid solutions after varius thermomechanical treatments. The density of states is calculated from the data of the electronic heat capacity. The results obtained are analysed alongside with similar results for the Cu-Al solid solutions. It is shown that the electronic density of states decreases with ordering in the alloys. This decrease attains 40% for some alloys and treatments. The concentration dependences of the electronic density of states are non-monotonous. A minimum is observed in the range where the short-range order is essential. The explanation of these results is given in terms of the inhomogeneous order model. According to this model regions with different types of SRO are formed in a-solid solutions. In the ideal case the type of ordering in these regions corresponds to higher concentration phases, while the ordering in the r-solid solution corresponds to a superstructure of LI,-type. The order type of these regions is defined by the temperature and concentration of the alloy. The model explanations are confirmed by calculations based on formulas obtained with the experimentally measured short-range order parameters.