The new and upgraded neutron instruments for material science at HMI current activities in cooperation with industry

Recent progress in engineering includes the development of new materials and innovations in their processing and treatments. Material technologies, like the study of metals, alloys, ceramics and composites, especially non destructive analyses of residual stresses profiles and textures, have gained an increasing importance. The dedicated residual stress diffractometers E3 and E7 at BENSC, HMI, Berlin are already equipped with new two dimensional position sensitive detectors. An upgrade of the monochromator system is planned for 2006 which includes perfectly bent silicon crystals in order to optimise both intensity and angular resolution yielding a large gain of the diffractometer efficiency for strain measurements. A range of equipment for sample positioning is available, such as a closed Eulerian cradle for samples with weights of up to 5 kg, a second cradle for heavy samples up to 50 kg with the ability to tilt the samples up to 90 and a translation table carrying samples of up to 300 kg and 1000 mm in diameter. Gauge volumes can be adjusted by a new computer controlled variable slitsystem in a range from 1x1x1 mm3 up to several mm3. In situ residual stress analysis can be performed within industrial components during mechanical or thermal loading up to 2000 K . Rapid data visualization as well as evaluation is performed by the specially designed software. The powder diffraction pattern is calculated by summation over the scattering angle dependent Debye Scherrer lines on the two dimensional 400 400 mm2 planar area detector. A large amount of beam time is exclusively used for industrial research. Among the components that were investigated are crankshafts, impellers, pistons, cylinder heads, turbine blades and welds. Both instruments are similarly designed, where E3 is set up for higher flux and therefore penetration depths and E7 is designed for higher angular resolutio

Efficiency boost of the materials science diffractometer E3 at BENSC One order of magnitude due to a horizontally and vertically focusing monochromator

The recent performance boost of E3, the residual strain and texture diffractometer at the HMI, Berlin, has enhanced significantly the experimental turnover as well as the quality of the measurement results. The instrument was equipped with a new vertically focusing and horizontally bent perfect Si single crystal monochromator, which optimizes the figure of merit for residual stress experiments. The increase in the figure of merit compared to the previous monochromator is more than a factor of 10. Diffraction is one of the most effective ways of determining residual stress fields non destructively and the three main types of diffraction methods, laboratory X ray, high energy synchrotron X ray, and neutron diffraction, have their own individual advantages. Neutron diffraction has the advantage of high penetration depth in all common crystalline engineering materials. For good quality and fast measurements an instrument must be as highly optimized as possible to serve the residual stress community efficientl