engleski

Heat Conduction in Complex Metallic Alloys

Thermal conductivity, κ, of ε-phase Al73Pd25Fe2 and "Bergman phase" Mg32(Al, Zn)49 is presented, which resembles features common to all complex metallic alloys: relatively low value, shallow local maximum or change of slope at approximatelly 50 K, and a rise above 100 K. Electron contribution is calculated using Wiedemann-Franz law, while the calculation of the phonon thermal conductivity below 50 K is calculated emloying Debye model. The sum of the two does not explain the experimental data at higher temperatures (above 100 K). This discrepancy is analyzed in three competitive ways: assuming an increase of an effective Lorenz number, taking into account hopping of localized lattice vibrations, and employing a "bipolar diffusion effect", known from theory of semiconductors. While results of the former two approaches confirm other findings in literature, "bipolar diffusion effect" needs to be adopted for the specific electron structure of complex metallic alloys.

thermal conductivity ; Wiedemann-Franz law ; Debye model ; localized lattice vibrations ; bipolar diffusion

Kao pozvano predavanje Ante Bilušić je ovaj rad prezentirao na međunarodnoj radionici "Frontiers in Complex Metallic Alloys" (cma2008.ifs.hr). S.I. posvećen Profesoru Boranu Leontiću.