Molecular Dynamics Simulations Of Solid-liquid Interfacial Property For Metals

This dissertation consists of four parts.In Chapter one, we made a brief review of the new achievement on the experimental and theoretical studies of the metallic solid-liquid interfacial kinetic coefficient and free energy in recent years.In Chapter two, we describe the fundamental issue of the molecular dynamics simulations method, and some important technique relevant current studies.In Chapter three, by using molecular dynamics simulation, the solid-liquid interfacial kinetic coefficient for hexagonal-close-packed Mg was calculated for three different orientations: [0001], [10 10] , [1120]. The comparison between MD results and the density function theory model was also given. The results show that the interface mobility was found to lie in the range 40-80 cm/s/K, μ₁₁₂₀ and μ₁₀₁₀ are found to be of comparable magnitude and apporoximately 1.7 times larger than μ₀₀₀₁.In Chapter four, combining the MD and the capillary fluctuation method(CFM), we calculate the crystal-melt interfacial free energies and its anisotropies for hexagonal-close-packed iron under high pressure. In this calculation, three pressure, namely 100 GPa, 200 GPa, 330GPa are considered. The results show that at high pressure, the atom is more like hard sphere, thus the configuration entropy may the leading term for the free energy .The anisotropy of crystal-melt interfacial free energies is much influenced by pressure. Our calculated results of Turnbull coefficients is about 2 times larger than that at ambient pressure for metals.