NDE of microstructured materials by x-ray diffraction and refraction topography
For the purpose of micro structural characterization X-ray topography reveals the spatially resolved scattering of materials and small components. It combines the advantages of radiographic imaging and the analytical information of wide and small angle X-ray scattering like phase distribution, texture, micro cracks, interfaces and pores. Scanning techniques at selected scattering conditions permit the topographic characterization of any crystalline or amorphous solid or liquid. Topographic methods and applications for the purposes of research, quality control and damage evaluation are presented.
Nondestructive evaluation of single fibre debonding in composites by X-ray refraction
Abstract Regarding the basic relevance of single fibre bonding for the mechanical properties of composites, relevant test methods are required. A new nondestructive method provides a fast and precise tool to determine the fraction of debonded fibres by refraction of X-rays at the interface of fibres in composites. The systematic analysis of thin walled unidirectional tapes of carbon fibres in thermoplastics results in specific characteristics of different lots. These were successfully exploited for the improvement of the processing parameters. Damage distributoon and flaw detection are imaged by two-dimensional scans of X-ray refraction topography.
Investigation of morphology-dependent fracture behaviour with the single-fibre pull-out test
Abstract In this study attempts are made to answer the question of how the morphology, and especially the transcrystallinity, influences the fibre/matrix adhesion in carbon-fibre/poly(phenylene sulphide) composites. Therefore, single-fibre pull-out measurements are performed with samples containing high-modulus (HM) and high-strength (HS) fibres that had been subjected to different thermal treatments. Transcrystallinity leads to a prevailing brittle fracture process in the interface and to higher values of the apparent shear strength. Samples with HS fibres and high crystallinity show an unexpected ductile fracture behaviour at a high apparent shear strength level.