X-ray studies on Debye characteristic temperatures of disordered binary substitutional alloys

An expression has been derived for the Debye characteristic temperatures of disordered binary substitutional alloys in terms of the Debye characteristic temperatures of the component metals, concentration of the solute atom and an unknown parameter which can be found from the Debye characteristic temperature of the alloy at any particular concentration. Debye temperatures of polycrystalline specimens of copper, nickel and copper-nickel (20, 30, 40, 50, 60, 80 and 90% nickel by weight) alloys have been determined by X-ray diffraction methods. Intensities of different reflexions have been measured with the help of a highly accurate counter-diffractometer technique and corrected for temperature diffuse scattering, diffuse scattering due to random distribution of guest atoms in host sites and difference in sizes of different atoms (in case of alloys only) and incorrect background. Debye temperatures have been plotted against concentration and the variation has been compared with theoretical predictions. Experimental results are found to agree satisfactorily with the predictions obtained during the present investigations.