Molecular Dynamic Simulation of Segregation in Rapidly Solidifying Silicon

点击翻译按钮获取中文摘要

The rapid solidification of silicon containing impurities will be studied via molecular dynamics simulations. The melt/solid interface moves at a rate of meters per second, so that local equilibrium is not attained. Properties such as the so-called segregation coefficient are no longer constants in these conditions. An understanding of many aspects of rapid solidification, such as impurity-host interactions, requires atomic-scale modeling of multicomponent systems using three- body forces between atoms. The proposed work will use the Stillinger- Weber potential and similar interparticle interactions. Particular attention will be given to impurity trapping, solute diffusivity, and trapping mechanisms. Results of atomic-scale simulations will be important in evaluating different possible models of solute trapping. They will thereby improve continuum-scale modeling of solute segregation. Solute segregation during rapid solidification is central to control formation of meta-stable alloys with novel corrosion resistance and catalytic properties, as are produced, for example, with laser annealing.