Lab-based in situ nanoCT as a tool for the 3D structural and mechanical characterization of metamaterials

The lab-based X-ray microscope Xradia 810 Ultra with mechanical in situ testing, here referred to as nanoCT, is a versatile tool for structural characterization of complex 3D samples down to 50 nm resolution with and without loading. The load stage is mounted on the CT rotation stage and can exert a maximum force of 0.8 N in compression and indentation experiments. This allows for the observation of microstructural changes as a function of mechanical load (and time). With its low energy X-ray source (Cr source, 5.4 keV), absorption and Zernike phase contrast, the nanoCT configuration is ideal for characterizing polymeric metamaterials at high spatial resolution.
Polymeric tetrahedral metamaterials manufactured using 3D direct laser writing method were characterized using the in situ nanoCT before and at different levels of loading. Differences in the structures were obtained scanning the samples in absorption and phase contrast modes, using a field of view of 65 μm and a voxel size of (128 nm)³. While the absorption contrast scan provides suitable images for the segmentation and the digital volume correlation, the phase contrast enhances the pores and defects within the microstructures. ... mehrFigure 1 shows the deformation of the beams of the tetrahedral sample before and after two levels of loading.