The solid, liquid, and solidification properties of Pd, Ag pure metals and especially PdxAg1-x alloys are studied by using the molecular dynamics simulation. The effects of temperature and concentration on the physical properties of Pdx$Ag1-x are analyzed. Sutton-Chen (SC) and Quantum Sutton-Chen (Q-SC) many-body potentials are used as interatomic interactions which enable one to investigate the thermodynamic, static, and dynamical properties of transition metals. The simulation results such as cohesive energy, density, elastic constants, bulk modulus, pair distribution functions, melting points and phonon dispersion curves obtained for Pd, Ag and PdxAg1-x are in good agreement with the available experimental data at various temperatures. The predicted melting points of Pd, Ag and their binary alloys by using Q-SC potential parameters are closer to experimental values than the ones predicted from SC potential parameters.
The liquid properties such as diffusion constants and viscosities computed from Q-SC potentials are also in good agreement with the available experimental data and theoretical calculations. Diffusion coefficients and viscosity results calculated from simulation obey the Arrhenius equation well. The coefficients of the Arrhenius equation are given in order to calculate the self-diffusion coefficient and shear viscosity of Pd-Ag alloys at the desired temperature and concentration.
Using different cooling rates, we investigate glass formation tendency and crystallization of Pd-Ag metal alloys, by analyzing pair distribution function, enthalpy, volume, and diffusion coefficient. Pd-Ag alloys show the glass structure at fast cooling rates while it crystallizes at slow cooling rates. Glass and crystallization temperatures are also obtained from the Wendt-Abraham parameter. The split of the second peak in the pair distribution function is associated with the glass transition. Glass forming ability increases with increasing concentration of Ag in Pd-Ag alloys.
Thermal and mechanical properties of Cu, Au metals and their ordered intermetallic alloys Cu3 Au(L12), CuAu(L10), and CuAu3(L12) are also studied to investigate the effects of temperature and concentration on the physical properties of Cu-Au alloys. The simulation results such as cohesive energy, lattice parameter, density, elastic constants, bulk modulus, heat capacity, thermal expansion, melting points, and phonon dispersion curves are in good agreement with the available experimental and theoretical data at various temperatures.
The Q-SC potential parameters are more reliable in determining physical properties of metals and their random and ordered alloys studied in this work
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12605467/index.pdf |
| Date | 01 September 2004 |
| Creators | Kart, Hasan Huseyin |
| Contributors | Tomak, Mehmet |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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