Molecular Dynamic Simulation of Segregation in Rapidly Solidifying Silicon

快速凝固硅中偏析的分子动力学模拟

• 批准号: 8821390
• 负责人: Lyle Ungar
• 金额: $ 13.36万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-06-15 至 1991-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8821390&HistoricalAwards=false
• 关键词: Molecular; Dynamic; Simulation; Segregation; Rapidly

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.

用分子动力学模拟方法研究含杂质硅的快速凝固过程。熔体/固体界面以每秒几米的速度移动，因此没有达到局部平衡。在这些条件下，诸如所谓的分离系数之类的性质不再是常量。要理解快速凝固的许多方面，如杂质与主体的相互作用，需要使用原子之间的三体力对多组分系统进行原子尺度的建模。这项拟议的工作将使用斯蒂林格-韦伯势和类似的粒子间相互作用。将特别注意杂质捕获、溶质扩散和捕获机制。原子尺度模拟的结果将是评估不同可能的溶质捕获模型的重要依据。因此，它们将改进溶质分离的连续尺度模拟。快速凝固过程中的溶质偏析是控制具有新型耐腐蚀性和催化性能的亚稳定合金形成的核心，例如，激光退火法就是这样产生的。