Non-destructive evaluation of strain-stress and texture in materials science by neutrons and hard X-rays

Abstract

Together with the microstructure residual stresses and crystallographic textures are important parameters in considering the application profile of engineering products. Both residual stress and crystallographic texture are related to identical grain arrangements. That means on one hand texture and strain influence each other and on the other hand both informations contribute to considering anisotropic materials properties, quality of welds, inhomogenous behaviour and so on. Non-destructive evaluations need experimental methods going deeply inside a material. Furthermore, it is necessary to handle complex and heavy samples. Neutrons and high-energy X-rays (about 100keV) have a high penetration power in the cm-range to fulfil these requirements. The instrumentation must be very flexible fitting the set-up for both investigations. The materials science diffractometer STRESS-SPEC at the Forschungsneutronenquelle Heinz Mayer-Leibnitz FRM II at Garching/Germany (neutron) and the HZG materials science beamline Harwi-II at Hasylab-Hamburg/Germany (synchrotron) are able for combined strain profile and texture gradient investigations non-destructively. The newly installed robot at STRESS-SPEC allows a very flexible sample manipulation for both types of experiments. First results are presented. Synchrotron radiations with higher brilliance are favoured for small gauge volume and fast measurements. That opens the field of in situ loading (tension-, compression-, cyclic loading) and in situ welding investigations.