Papers by Keyword: Local Tomography

Abstract: X-ray CT method is a kind of nondestructive inspection, but has strong limitation in sample size due to a small field of view (FOV). The higher the resolution, the smaller FOV is, mainly due to the element number of available detectors commercially. Therefore, sample machining is more or less necessary so that the sample size is fit within the small FOV in the case of the high-resolution observation. Local tomography technique enables a high resolution reconstruction of small region of interests within a sample without the sample machining. In this study, we have evaluated the size effects of aluminum foam samples in terms of the 3D image quality by the local tomography techniques.

Abstract: Synchrotron X-ray microtomography has been utilized for the 3D characterisation of microstructure of aluminium foams. A combination of phase contrast imaging technique and several application techniques, such as local area tomography, microstructural gauging and in-situ observation, has enabled the assessment of microstructural effects on compressive deformation behaviours. It has been clarified that ductile buckling of a cell wall occurs regardless of any of the above microstructural factors in the case of a pure aluminium foam, while rather brittle fracture of a cell wall is induced by the existence of coarse micro-pores independently of the intermetallic particles and the grain boundary in the case of Al-Zn-Mg alloy foams. When cooling rate during foaming is high, however, lower energy absorption might be attributable to the significant amount of residual foaming agent particle and its inhomogeneous distribution. These tendencies are also confirmed by 3D strain mapping by tracking internal microstructural features.