TY - CHAP
T1 - X-ray microtomography
T2 - Characterisation of structures and defect analysis
AU - Harrer, Bernhard
AU - Kastner, Johann
N1 - Funding Information:
The authors gratefully acknowledge the contributions of: Professor H.P. Degischer and his colleagues from the Vienna University of Technology, Institute of Materials Science and Technology for their support and useful input; M. Reiter, B. Plank, D. Salaberger and P. Orgill from the Upper Austria University of Applied Sciences; metallographic investigations of non-metallic inclusions by voestalpine Stahl AG; the provision of samples by the companies AMAG AG, FACC AG, Georg Fischer AG, Gruber & Kaja GmbH, Honsel AG, MPI-IPP Garching and TCKT GmbH. The project was supported by the COMET program of the FFG and Austrian research funds (FWF).
PY - 2011
Y1 - 2011
N2 - Determination of the three-dimensional (3D) distribution of heterogeneities and structures is of primary concern in the field of materials characterisation and quality control. Heterogeneities may create exploitable property profiles, but they can also degrade reliability and are therefore classified as defects. The quantitative description of heterogeneities is a prerequisite for evaluating their effects and potential for strengthening or degrading a material. Knowledge of the size, shape, location and arrangement of heterogeneities enables the evaluation of the quality of materials and work pieces. Micro-focus X-ray computed tomography (XCT) with flat-panel matrix detectors is the current method of measuring variously absorbing inner or hidden structures without destroying the object. The size and topology of different types of heterogeneities can vary greatly. The different size scales of the heterogeneities and of the affected material volume require appropriate tomographic methods and resolutions. XCT provides statistically significant estimates of volume fractions of heterogeneities in materials depending on the spatial and contrast resolution. The characterisation and quantification of heterogeneities in polymeric materials, light metals, Fe-based materials, metallic foams and metal matrix composites are presented by means of cone beam XCT. Micro-focus and sub-micro-focus X-ray tubes may record intensities related to a minimum volume (voxel size) of (3 μm)3 and (0.4 μm)3, respectively. Spatial resolution also depends on the contrast of the heterogeneity and is usually reliable for features >20 voxels. Suitable evaluation routines are introduced and rules for the detectability and classification of contrast and shape are specified. The architecture of the reinforcement in composite materials is presented and quantified in terms of size distribution, orientation and connectivity. Alignments and the formation of the dendritic structure in cast metals are shown in 3D. A method for differentiation of various heterogeneities which are simultaneously present in one material system is presented. The microstructural features are verified using target metallographic techniques. Thus, important 3D structural information can be achieved to understand their correlation with processing.
AB - Determination of the three-dimensional (3D) distribution of heterogeneities and structures is of primary concern in the field of materials characterisation and quality control. Heterogeneities may create exploitable property profiles, but they can also degrade reliability and are therefore classified as defects. The quantitative description of heterogeneities is a prerequisite for evaluating their effects and potential for strengthening or degrading a material. Knowledge of the size, shape, location and arrangement of heterogeneities enables the evaluation of the quality of materials and work pieces. Micro-focus X-ray computed tomography (XCT) with flat-panel matrix detectors is the current method of measuring variously absorbing inner or hidden structures without destroying the object. The size and topology of different types of heterogeneities can vary greatly. The different size scales of the heterogeneities and of the affected material volume require appropriate tomographic methods and resolutions. XCT provides statistically significant estimates of volume fractions of heterogeneities in materials depending on the spatial and contrast resolution. The characterisation and quantification of heterogeneities in polymeric materials, light metals, Fe-based materials, metallic foams and metal matrix composites are presented by means of cone beam XCT. Micro-focus and sub-micro-focus X-ray tubes may record intensities related to a minimum volume (voxel size) of (3 μm)3 and (0.4 μm)3, respectively. Spatial resolution also depends on the contrast of the heterogeneity and is usually reliable for features >20 voxels. Suitable evaluation routines are introduced and rules for the detectability and classification of contrast and shape are specified. The architecture of the reinforcement in composite materials is presented and quantified in terms of size distribution, orientation and connectivity. Alignments and the formation of the dendritic structure in cast metals are shown in 3D. A method for differentiation of various heterogeneities which are simultaneously present in one material system is presented. The microstructural features are verified using target metallographic techniques. Thus, important 3D structural information can be achieved to understand their correlation with processing.
UR - http://www.scopus.com/inward/record.url?scp=84874279635&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-17782-8_6
DO - 10.1007/978-3-642-17782-8_6
M3 - Chapter
SN - 9783642177811
T3 - Advanced Structured Materials
SP - 119
EP - 149
BT - Fabrication and Characterization in the Micro-Nano Range :New Trends for Two nd Three Dimensional Structures
PB - Springer
ER -