Particle tracking during Ostwald ripening using time-resolved laboratory X-ray microtomography
Particle tracking during Ostwald ripening using time-resolved laboratory X-ray microtomography
复制标题
DOI：
10.1016/j.matchar.2014.01.022
复制
发表时间：
2014-04
影响因子：
4.7
通讯作者：
Thomas Werz;M. Baumann;U. Wolfram;C. Krill
中科院分区：
文献类型：
--
作者：
Thomas Werz;M. Baumann;U. Wolfram;C. Krill
研究了实验室 X 射线显微断层扫描，作为获得奥斯特瓦尔德熟化过程中 Al-5 wt.% Cu 半固态样品微观结构粗化的时间分辨图像的方法。由于断层扫描的 3D 成像能力，该技术能够独特地获取单个颗粒的生长速率，从而不仅可以对粗化进行统计表征（传统金相学早已可以实现这一点），而且还可以量化局部环境对颗粒边界迁移的影响。后一信息对于理解粗化阶段高体积分数奥斯特瓦尔德熟化过程中的生长动力学至关重要。开发了自动图像处理和分割例程，以缩小颗粒边界网络中的间隙，并跟踪从一个退火步骤到下一个退火步骤的单个颗粒。粒子跟踪成功率对任何给定粒子的分割错误可能性的上限仅为百分之几。从时间分辨断层扫描重建中提取的粒径轨迹的精度相应较高。统计平均粗化数据和单个颗粒生长速率与先前实验研究的结果以及奥斯特瓦尔德熟化的计算机模拟非常一致。
Laboratory X-ray microtomography is investigated as a method for obtaining time-resolved images of microstructural coarsening of the semisolid state of Al–5 wt.% Cu samples during Ostwald ripening. Owing to the 3D imaging capability of tomography, this technique uniquely provides access to the growth rates of individual particles, thereby not only allowing a statistical characterization of coarsening—as has long been possible by conventional metallography—but also enabling quantification of the influence of local environment on particle boundary migration. The latter information is crucial to understanding growth kinetics during Ostwald ripening at high volume fractions of the coarsening phase. Automated image processing and segmentation routines were developed to close gaps in the network of particle boundaries and to track individual particles from one annealing step to the next. The particle tracking success rate places an upper bound of only a few percent on the likelihood of segmentation errors for any given particle. The accuracy of particle size trajectories extracted from the time-resolved tomographic reconstructions is correspondingly high. Statistically averaged coarsening data and individual particle growth rates are in excellent agreement with the results of prior experimental studies and with computer simulations of Ostwald ripening.