On the grain size dependent solute and particle drag

2019-11-13 12:56:41

model grain growth size dependent

责任者: Rabkin, E. 单位: Dept. of Mater. Eng., Technion-Israel Inst. of Technol., Haifa, Israel 来源出处: Scripta Materialia(Scr. Mater. (USA)),2000/06/13,42(12):1199-206 摘要: It is shown that the grain size dependent solute drag decreases the rate of grain growth in nanocrystals but is incapable to stop it completely. In the framework of uniform boundary model the parabolic grain growth law is transformed into a mixed cubic-parabolic law. The model of grain size dependent particle drag is developed. This model is relevant for the nanocrystal with the grain boundaries (GBs) saturated with impurities from the early beginning of grain growth process. The excess impurities precipitate in the GB particles which then exert the pinning force on GBs. The model demonstrates the dynamic behaviour very similar to the behaviour of the model with the grain size dependent solute drag. The process of grain growth cannot be stopped. It is shown that at the initial stages the grain growth process can be associated with the series of the breakaway events of the GBs from the dragged particles. At the later stages the steady-state growth is stable and no breakaway occurs. The kinetic grain growth diagram is constructed which describes the character of grain growth and GB migration (jerky or steady state) 关键词: grain boundaries;grain growth;grain size;impurities;nanostructured materials;grain size dependent solute drag;mixed cubic-parabolic law;nanocrystals;uniform boundary model;parabolic grain growth law;grain size dependent particle drag;impurities;grain growth process;excess impurities;pinning force;breakaway events;dragged particles;steady-state growth;kinetic grain growth diagram;steady state;jerky state;nanocrystalline materials