Molecular Dynamics Simulation Of The Anisotropy For Melting Process Of Single-crystal Aluminum

Al is one of the main chemical constituent of the earth. And at the same time, as one of the simple metal, it has been widely used in our daily life and industrial production. So the research of A1 has important significance for material science, condensed matter physics and geophysics. For all of the research of Al, the research of melting process has attracted much attention for a long time.In this thesis, molecular dynamics simulations employing an embedded atom method potential are used to investigate the (100) and (110) surfaces melting and bulk melting processes of single-crystal aluminum. The volume and internal energy of the system during bulk melting process are analyzed by radial distribution function and coordination number. The movements of the solid-liquid interface during surface melting process are observed and the velocity of melting is calculated for all the surfaces at different temperatures.The simulation results show that the volume and internal energy in the system shows a sudden increase between 1200 K and 1205k in bulk melting process and the solid-liquid interface retain still at 985K and 955K in the (100) and (110) surfaces melting process. The melting velocity of (110) surface is greater than (100) surface. So we concluded that the surface melting is anisotropic for different surfaces. The melting points of (100) and (110) is 985K and 955K which agrees with the experimental data.The simulation results show that the bulk melting point is 1205K which is higher than the surface melting point. This is because of the different mechanisms of the two melting process. Surface melting is significant in real melting process but bulk melting is caused by the instability of lattice elastic. Thus it can be concluded that the present melting point simulation method is correct and effective, and the Adams’s embedded atom potential is suitable for dealing with metal Al systems.