Dealing with Missing Angular Sections in NanoCT Reconstructions of Low Contrast Polymeric Samples Employing a...

Area of Science:

• Materials Science
• Engineering
• Imaging Technology

Background:

• In situ experiments are crucial for assessing materials with complex microstructures.
• Lab-based computed tomography (CT) systems enable time-lapsed mechanical testing.
• Limited X-ray acquisition angles (e.g., 140°) in CT can cause data gaps, especially for low-contrast materials.

Purpose of the Study:

• To investigate strategies for improving data acquisition in in situ CT experiments with limited angular range.
• To demonstrate methods for achieving accurate 3D microstructure reconstruction despite imaging challenges.

Main Methods:

• Utilized a lab-based computed tomography system (Xradia 810 Ultra) for in situ mechanical testing.
• Scanned low-contrast polymeric samples (tetrahedral microlattice and structured markers) over 140° and 180° acquisition angles.
• Applied sample rotation strategies to optimize X-ray illumination and data collection.

Main Results:

• Limited acquisition angles (140°) result in regions of low information gain, leading to inaccurate reconstructions.
• Missing structural details due to limited angles are confined to an approximately 20° angular wedge.
• A 90° sample rotation improved X-ray absorption and enabled accurate reconstruction of the tetrahedral microlattice geometry.

Conclusions:

• Simple sample positioning strategies can significantly improve data quality in in situ CT.
• Accurate 3D reconstruction of complex microstructures is achievable even with restricted scanning.
• Optimizing sample orientation is key for successful in situ mechanical assessment of materials using CT.