Molecular Dynamics Simulation Of Energy And Microstructural Evolution Of Silver Nanocrystals

In recent years, nanometer materials are more and more widely in use. especially noble metal nanometer materials are one of great mass fervour in nanometer materials domanial. Energy and microstructure evolution of the Ag nanocrystalline in the process of high-temperature relaxation are investigateds with embedded atomic methods(EAM) and molecular dynamics simulation.First, the quasi-cubic Ag nanocrystal which is cut along the inter-perpendicular facet of {110}, {211} and {111},systems’ s temperature and size are both have effects on energy distribution of atoms: In the same systems,its average energy of atoms increase when its temperature rise, different systems have the same distribution density of atomic energy,but high proportion at high energy region and their energy are more disperse when systems have small sizes.we also find by simulation that average energy of atoms increase linear with temperature rise,when temperature get to a certain temperature the systems have saltation of energy,saltation temperature rely on system’s size,small size have low saltation temperature.Then,change of systems’ s energy make arrangement of atoms alter,whith the temperature of Ag nanocrystalline rize,its structure from regular cubic,aotm’s removal and regoup appear at apex the first, edge the second and surface the last to sphere. The melting process shows that there are tree stages in high melting:premelting of surface in a twinking,surface atom in disorder and rearrangement in long-playing,comprehensive melting rapidly.atom move and rearrangement are appear at apex the first,edge the second and surface the last,it result in low energy of nanocrystalline’s surface area and decrease energy of system.In addition,there are obviously anisotropic behaviors in the processes of Ag nanocrystalline: The thermal-stability is decreasing in the sequence of facet ( 111), facet(110),and facet)211(.Three different facets are extremely short and show no evidently difference with each other. However considering facet with the same crystal plane indices,the lifetimes are relatively longer within the third layer of atoms and subtly increase with the increment of the layer number of atoms. The lifetimes are distinctly different with each other among the three different facets within the third layer of atoms.The lifetimes of three different facets within the third layer of atoms have obviously anisotropic behaviors, facet)211( is the shortest,the longerest is facet ( 111),and facet(110) is between them.