X-ray imaging and computed tomography for engineering applications

Abstract

After an incremental development which took place over four decades, X-ray imaging has become an important tool for non-destructive testing and evaluation. Computed Tomography (CT) in particular beholds the power of determining the location of flaws and inclusions (e. g. in castings and composites) in three-dimensional object coordinates. Therefore, and thanks to a speed-up of the measurement, CT is now routinely considered for in-line inspection of electronics, castings and composites. When precision and not speed is important, Micro-CT (μCT) can be employed for Dimensional Measurements (DM, e. g. quality assurance and shape verification), as well as for in situ testing, and for characterizing micro-structures in metals and composites. Using appropriate image processing and analysis μCT can determine the local fibre orientation in composites, the granular morphology of battery cathodes or the inter-connectivity of certain phases in casting alloys.Today, the large variety of X-ray instruments and methods poses an application problem which requires experience and a lot of knowledge for deciding which technique applies best to the task at hand. Application-specific guidelines exist for X-ray radiography testing (RT) only, whereas standardization has been applied to CT, unfortunately leaving out high resolution subμ CT, and nano-CT. For the latter exist an equally high number of NDT applications, however these instruments still necessitate a profound expertise. The task is to identify key industrial applications and push CT from system standardization to application specific automation.

Mapping Magnetic Signals of Individual Magnetite Grains to Their Internal Magnetic Configurations Using Micromagnetic Models

“…Current technology may partly fall short of reaching sufficient tomographic resolution, in particular for grains in a size range below a few microns, which can be modeled with the current computational capacities. Although commercial microCT instruments do not yet allow for a routine scanning of nm voxel densities, recent advances in tomographic techniques (Lutter et al., 2021 ; Zabler et al., 2021 ), such as X‐ray nano tomography (nanoCT), have improved the maximal imaging resolution below the micrometer scale, and hence it might be possible to empirically test this investigation in sufficiently small grains. Furthermore, FIB‐nt already offers the capacity to profile a grain geometry with a few nanometers size resolution (Lutter et al., 2021 ; Nikolaisen et al., 2020 ), although it is a destructive technique that requires to perform the magnetometry scanning before applying the tomographic measurement.…”

Extending the measurement capabilities of 3D X-ray microscopy to dimensional metrology

“…3, right-or alternatively, Refs. [15][16][17]). The scintillator-lens-CCD coupling is used for the indirect conversion of X-ray photons into electrically charged signals.…”

Source-detector trajectory optimization in cone-beam computed tomography: a comprehensive review on today’s state-of-the-art

“…CBCT is also relevant for industrial applications (Zabler et al 2021), especially in materials research and quality control. A high variety of objects is examined.…”