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The concept of “ordering or alloying potential” (J. Hafneri: from Hamiltonians to phase diagrams: Springer Berlin 1987 and R. N. Singh and F. Sommerii Rep. Prog. Phys. 60 (1997) 57–150) enables the understanding of the different kind of alloys: hetero-coordinated one’s leading to compounds, homocoordinated ones leading to miscibility gap systems and substitutional alloys. The ordering potential is based on the comparison of identical atom interionic potentials (V11 and V22) and different atom interionic potential (V12) It allows the description of the demixing properties of some alloys. In order to understand the concepts, we developed our calculations by using a Lennard-Jones potential, the atomic structure being calculated by molecular dynamics simulation. We obtained surprising and unexpected results putting in evidence the time of simulation and the strength of the ordering potential.

Recently, we (Es Sbihi Phil. Mag 2010) have successfully calculated, by molecular dynamics, the static structure factor of liquid bismuth at different temperatures. Our results were in very good agreement with the Waseda experimental data. Our assumption was to consider the true density of states which presents a gap as measured by Indlekofer (J. Non-Cryst. Solids 1989) and calculated by Hafner-Jank (Phys. Rev. B 1990) for liquid bismuth. The number of electrons at the Fermi energy has been calculated with three conduction electrons for bismuth (number of p electrons). With this assumption, the structures were determined with an effective ion-ion potential constructed from the Shaw local Optimised Model Potential (OMP) and the Ichimaru-Utsumi dielectric function. In the present paper, we generalize our assumptions to liquid thallium and lead which also present such a gap. Their calculated structures are also very close to the experimental ones. This confirms that the number of conduction electrons on the Fermi sphere is consistent with the number of p electrons as has been even shown for our electronic transport properties of liquid lead (A. Ben Abdellah, Phys. Rev. B 2003).

Pseudopotential formalism is used to construct an ionic effective potential (ion-ion potential screened by electrons). Molecular Dynamics is used in conjunction with the constructed effective potential to get the atomic structure factor of the pure components copper and tin which are compared to the experimental ones. We selected the Shaw Optimized Model Potential having proved that it adequately describes the atomic structure, we used it to calculate the velocity autocorrelation function and to deduce the self diffusion of pure metals: copper, tin and the diffusion coefficient of copper in the Sn95,6%Cu4,4% .

In this paper, the electronic transport properties of as-spun Zr66.7Ni33.3 alloys were studied in detail by a combination of electrical resistivity and absolute thermoelectric power measurements over a temperature range from 25 up to 400 °C. Moreover, the isochronal and isothermal crystallization kinetics of Zr66.7Ni33.3 glassy alloy has been investigated based on the electrical resistivity measurements. The comparative study of the crystallization kinetics of these binary amorphous alloys was carried out, for the first time to our knowledge, using an accurate method for electrical resistivity measurements. In the isochronal heating process, the apparent activation energy for crystallization was determined to be, respectively, 371.4 kJ mol−1 and 382.2 kJ mol−1, by means of Kissinger and Ozawa methods. The Johnson–Mehl–Avrami model was used to describe the isothermal transformation kinetics, and the local Avrami exponent has been determined in the range from 2.97 to 3.23 with an average value of 3.1, implying a mainly diffusion-controlled three-dimensional growth with an increasing nucleation rate. Based on an Arrhenius relationship, the local activation energy was analyzed, which yields an average value Ex = 376.2 kJ mol−1. [ABSTRACT FROM AUTHOR]