Okuma Gaku, Watanabe Shuhei, Shinobe Kan, Nishiyama Norimasa, Takeuchi Akihisa, Uesugi Kentaro, Tanaka Satoshi, Wakai Fumihiro
Laboratory for Materials and Structures Laboratory, Institute of Innovative Research, Tokyo Institute of Technology, R3-23 4259 Nagatsuta, Midori, Yokohama, 226-8503, Japan.
Japan Synchrotron Radiation Research Institute, JASRI/SPring-8, Kouto 1-1-1, Sayo, Hyogo, 679-5198, Japan.
Sci Rep. 2019 Aug 12;9(1):11595. doi: 10.1038/s41598-019-48127-y.
The characterization of the processing-induced defects is an essential step for developing defect-free processing, which is important to the assurance of structural reliability of brittle ceramics. The multiscale X-ray computed tomography, consisting of micro-CT as a wide-field and low-resolution system and nano-CT as a narrow-field and high-resolution system, is suitable for observing crack-like defects with small length and with very small crack opening displacement. Here we applied this powerful imaging tool in order to reveal the complicated three-dimensional morphology of defects evolved during sintering of alumina. The hierarchical packing structure of granules was the origin of several types of strength-limiting defects, which could not be eliminated due to the differential sintering of heterogeneous microstructures. This imaging technique of internal defects provides a link between the processing and the fracture strength for the development of structural materials.
加工诱导缺陷的表征是开发无缺陷加工工艺的关键步骤，这对于确保脆性陶瓷的结构可靠性至关重要。多尺度X射线计算机断层扫描由作为宽视野低分辨率系统的微CT和作为窄视野高分辨率系统的纳米CT组成，适用于观察长度小且裂纹开口位移非常小的裂纹状缺陷。在此，我们应用这种强大的成像工具来揭示氧化铝烧结过程中演变出的缺陷的复杂三维形态。颗粒的分层堆积结构是几种强度限制缺陷的根源，由于异质微观结构的差异烧结，这些缺陷无法消除。这种内部缺陷成像技术为结构材料的开发提供了加工与断裂强度之间的联系。
