Papers by Keyword: Energy Dispersive

Abstract: Through the combination of two or more materials to one compound, for example high-strength steel and aluminum, hybrid massive components can be manufactured, whose properties are specially adapted to the respective application. One of the challenges is the joining zone which is influenced by machining induced residual stresses. In order to examine the residual stress modifications by the machining process and in addition to analyze the influence of these residual stress gradients on the lifespan of hybrid components a non-destructive method of measuring depth-resolved residual stress is necessary. Therefore, an innovative energy dispersive X-ray measurement technique is used in the collaborative research center 1153 (CRC 1153). In this study the suitability of the method is examined by comparing the results with the angle dispersive method both in machined front surface of mono materials and hybrid shafts. A parametrical study shows the possibility to get greater depth information by variation of the measuring parameters Bragg angle, tilting angle, collimator and current. In addition, the results of the energy dispersive method combined with electrolytic removal is shown. Based on these results the evaluation of the reliability and reproducibility of energy dispersive residual stress measurements is completed.

Abstract: In this paper we discuss certain aspects of residual stress measurements using energy-dispersive synchrotron X-ray diffraction using very high X-ray energies in the range up to 200keV. In particular, we focus on the strain resolution and its relation to the geometric contribution to the instrumental resolution. This energy range together with the brilliance of insertion devices allows measurements in bulk materials with penetration approaching those of neutrons, and the technique is demonstrated to have a high potential for residual stress determination. However, the use of high X-ray energies implies a relatively small diffraction angle and in turn a relatively elongated gauge volume, which favours the application of the technique to essentially 2D problems.

Abstract: X-rays transmission stress analysis was tested on a 2mm thick steel sheet using energy dispersive X-rays diffraction (EDXD) and an industrial radiography equipment as X-ray source. A complex state of residual stresses was created in the sheet before the test and modified during the experiment by the way of a in-situ tensile test. In the diffracted beam spectrum, the energy peak displacement was related to macroscopic stresses using the elementary Mohr’s circle formalism for plane stress analysis. The change in the stresses thus analyzed is compared with the applied stress.