Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany.
Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany.
Sci Rep. 2023 Jan 19;13(1):1055. doi: 10.1038/s41598-022-27035-8.
Hierarchical guidance is developed for three-dimensional (3D) nanoscale X-ray imaging, enabling identification, refinement, and tracking of regions of interest (ROIs) within specimens considerably exceeding the field of view. This opens up new possibilities for in situ investigations. Experimentally, the approach takes advantage of rapid multiscale measurements based on magnified projection microscopy featuring continuous zoom capabilities. Immediate and continuous feedback on the subsequent experimental progress is enabled by suitable on-the-fly data processing. For this, by theoretical justification and experimental validation, so-called quasi-particle phase-retrieval is generalised to conical-beam conditions, being key for sufficiently fast computation without significant loss of imaging quality and resolution compared to common approaches for holographic microscopy. Exploiting 3D laminography, particularly suited for imaging of ROIs in laterally extended plate-like samples, the potential of hierarchical guidance is demonstrated by the in situ investigation of damage nucleation inside alloy sheets under engineering-relevant boundary conditions, providing novel insight into the nanoscale morphological development of void and particle clusters under mechanical load. Combined with digital volume correlation, we study deformation kinematics with unprecedented spatial resolution. Correlation of mesoscale (i.e. strain fields) and nanoscale (i.e. particle cracking) evolution opens new routes for the understanding of damage nucleation within sheet materials with application-relevant dimensions.
本文提出了一种用于三维（3D）纳米尺度 X 射线成像的分层指导方法，能够识别、细化和跟踪标本中超出视场的感兴趣区域（ROI）。这为原位研究开辟了新的可能性。在实验中，该方法利用基于具有连续缩放功能的放大投影显微镜的快速多尺度测量。通过合适的实时数据处理，可以对后续实验进展进行即时和连续的反馈。为此，通过理论论证和实验验证，将所谓的准粒子相位恢复方法推广到了锥束条件，与用于全息显微镜的常见方法相比，这对于足够快速的计算是关键，而不会显著损失成像质量和分辨率。利用特别适合于横向扩展板状样品 ROI 成像的 3D 层析成像，通过在工程相关边界条件下对合金板内的损伤成核进行原位研究，证明了分层指导的潜力，为在机械载荷下的空穴和颗粒簇的纳米级形态发展提供了新的见解。结合数字体素相关技术，我们以前所未有的空间分辨率研究了变形运动学。细观（即应变场）和纳米级（即颗粒开裂）演化的相关性为理解具有应用相关尺寸的板材内的损伤成核开辟了新的途径。
