Ordering the bubbles of closed-cell aluminum foams can contribute to decorative esthetics and create directional mechanical properties that disordered foams do not have. High-porosity (>80%) aluminum foams prepared by the traditional static gas injection method usually have large and polyhedral cells, which do not form an ordered stacking. Aluminum foams with relatively uniform and small cells (cell size ≈1.2 mm) have been recently obtained by gas injection through a nozzle rotating at high speed. Herein, the stacking of aluminum foams with different cell sizes and a monodisperse aqueous foam are characterized by X-ray tomography and compared with an ideal face-centered cubic (FCC) structure. The aluminum foam featuring the smallest cells has a concentrated distribution of cell coordination number with a peak of 12 and the first peaks of the radial distribution function are found to be consistent with those of the monodisperse aqueous foam and an ideal FCC structure. Furthermore, many aligned bubble chains with more than five bubbles are observed on cross-sectional images. Therefore, aluminum foam can become short-range ordered whenever the cell size is uniform enough and reduced to around 1.2 mm. Methods for further improving the order of aluminum foam are discussed.

中文翻译：

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短程有序铝泡沫

对闭孔铝泡沫的气泡进行排序有助于装饰美感，并产生无序泡沫所不具备的定向机械性能。传统静态注气法制备的高孔隙率（>80%）泡沫铝通常具有较大的多面体泡孔，不形成有序的堆积。最近通过高速旋转的喷嘴通过气体喷射获得了具有相对均匀和小孔（孔尺寸≈1.2 mm）的泡沫铝。在此，通过 X 射线断层扫描表征了具有不同孔尺寸的泡沫铝和单分散水性泡沫的堆叠，并与理想的面心立方 (FCC) 结构进行了比较。泡孔最小的泡沫铝泡孔配位数集中分布，峰值为12，径向分布函数的第一个峰值与单分散水性泡沫的峰值一致，具有理想的FCC结构。此外，在横截面图像上观察到许多具有五个以上气泡的对齐气泡链。因此，只要泡孔尺寸足够均匀并减小到 1.2 毫米左右，泡沫铝就可以成为短程有序。讨论了进一步提高泡沫铝有序度的方法。只要泡孔尺寸足够均匀并减小到 1.2 毫米左右，泡沫铝就可以成为短程有序。讨论了进一步提高泡沫铝有序度的方法。只要泡孔尺寸足够均匀并减小到 1.2 毫米左右，泡沫铝就可以成为短程有序。讨论了进一步提高泡沫铝有序度的方法。