Kinetics of heterogenous nucleation and growth

异质成核和生长动力学

• 批准号: 51463015
• 负责人: Professor Dr.-Ing. Gerhard Wilde
• 金额: --
• 依托单位: Institut für Materialphysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/51463015?language=en
• 关键词: Kinetics; heterogenous; nucleation; growth

Utilizing the stochastic nature of nucleation, nucleation kinetics parameters, specifically the nucleation barrier heights and the nucleation rates are determined experimentally. Thus, measurements are conducted that allow statistically analyzing the experimental data concerning the nucleation rate without applying a specific nucleation model. These data shall be obtained for large undercooling intervals corresponding to several orders of magnitude variations in the nucleation rates. For this reason, conventional and micro-chip calorimetry shall be employed. With a recently established combination of repeated solidification cycling using an interrupted melting procedure, heterogeneous nucleation can be studied for defined and known nucleant phases where the nucleant phase consists of the same elements as the binary alloy. Additionally, this method allows investigating the impact of the shape and the morphology of the nucleant phases or of their abundance on nucleation and growth. Thus, systematic variations of the structure of the intrinsic heterogeneous phase, of its volume fraction and of the morphology of its interface with the melt will be used for comparing the experimentally obtained data with atomistic – and phase field simulations performed in collaborative projects.

利用成核的随机性，成核动力学参数，特别是成核势垒高度和成核速率的实验确定。因此，进行测量，允许统计分析有关成核速率的实验数据，而不应用特定的成核模型。这些数据应在对应于成核率几个数量级变化的大过冷间隔下获得。为此，应采用常规和微芯片量热法。随着最近建立的重复固化循环的组合，使用中断的熔化程序，异质成核可以研究定义和已知的成核相，其中成核相由与二元合金相同的元素组成。此外，该方法允许研究成核剂相的形状和形态或其丰度对成核和生长的影响。因此，系统的变化的结构的固有的非均相，其体积分数和其与熔体的界面的形态将用于比较实验获得的数据与原子和相场模拟在合作项目中进行。