Statistical model of grain growth in polycrystalline nanomaterials
|Thomas B. Tengen 3, Tomasz Wejrzanowski 1,2, Radosław Iwankiewicz 3, Krzysztof J. Kurzydlowski 1,2|
1. Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland
Nanomaterials, due to their fine grain size, exhibit enhanced mechanical properties. However, their low stability at relatively low temperatures might limit their future applications.
In the present work, a statistical model has been proposed in order to study grain growth processes in nanomaterials. The Hillert’s approach has been extended by incorporating two mechanisms of grain growth for an individual grain: grain boundary migration (diffusion based - continuous) and grain rotation (discontinuous). The influence of the grain size distribution on the grain growth process has been studied.It has been shown that higher rate of rotations results in aberration from the parabolic law of grain growth. Such a deviation has also been observed experimentally, especially in grain growth in nanomaterials. The results reveal that growth rate increases with higher dispersion of the fine grains and the rotation mechanism can initiate growth even with low dispersion. This causes a steady increase in the coefficient of variation which, after some time interval, decays to homogeneity. It is also found that the varying misorientation angle affects the mobility constant.
Presentation: Poster at E-MRS Fall Meeting 2006, Symposium H, by Tomasz Wejrzanowski
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-07-21 14:00 Revised: 2009-06-07 00:44