BEER - The Beamline for European Materials Engineering Research at the ESS

The Beamline for European Materials Engineering Research (BEER) will be built at the European Spallation Source (ESS). The diffractometer utilizes the high brilliance of the long-pulse neutron source and offers high instrument flexibility. It includes a novel chopper technique that extracts several short pulses out of the long pulse, leading to substantial intensity gain of up to an order of magnitude compared to pulse shaping methods for materials with high crystal symmetry. This intensity gain is achieved without compromising resolution. Materials of lower crystal symmetry or multi-phase materials will be investigated by additional pulse shaping methods. The different chopper set-ups and advanced beam extracting techniques offer an extremely broad intensity/resolution range. Furthermore, BEER offers an option of simultaneous SANS or imaging measurements without compromising diffraction investigations. This flexibility opens up new possibilities for in-situ experiments studying materials processing and performance under operation conditions. To fulfil this task, advanced sample environments, dedicated to thermo-mechanical processing, are foreseen

A utilização da difração de neutrões na determinação do perfil de tensões residuais em revestimentos por soldadura

A técnica de difração de neutrões é usada neste artigo para estudar amostras ferríticas, revestidas comaços inoxidáveisausteníticos através de soldadura por arco submerso. Este procedimento é frequentemente usado no fabrico de equipamentos de processo para as indústrias química e nuclear, por facilidade de execução e razões económicas. A principal desvantagem deste processo de revestimento é a fissuração que frequentemente ocorre na interface material base/soldadura, potenciada pela presença de tensões residuais resultantes da operação de soldadura, a qual pode ser minimizada com a realização de tratamentos térmicos de relaxação de tensões. As amostras foram produzidas a partir de placas em aço ao carbono, tendo uma das superfícies sido revestida com dois tipos de aço inoxidável. Para a primeira camada foi usado um elétrodo EN 12072 - S 23 12 2 L e para a segunda e a terceira camadas foi usado um elétrodo EN 12072 - S 19 12 3 L. Após a soldadura, as amostras foram submetidas a um tratamento térmico de relaxação de tensões, durante 1 hora, à temperatura de 620ºC. Os perfis de tensões residuais obtidos por difração de neutrões evidenciam a relaxação de tensões residuais após o tratamento térmico realizado. A técnica de difração de neutrões revelou-se muito adequada na avaliação de tensões residuais neste tipo de ligações

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

AbstractTogether 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