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Eingeladener Vortrag
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Role of materials data
(2017)
In a general sense, data are the output of experimental research work. In this workshop we will present some basic ideas concerning the reliability of experimental data; this is a central issue both for individuals or labs producing results as well as for scientists working on theoretical models and engineers designing a machine. Digitalization accelerates enormously the data exchange between these communities; however, the required level of confidence on experimental results increases in the same way. We invite all the participants to reflect upon the value of materials data for their own work.
The advent of the Industrial Revolution was accompanied by several accidents of dramatic dimensions. The analysis of these events was the fundament for the continuous improvement in the reliability of technical systems. In the year 1871 the Prussian state created a technical institution dedicated for this task – the origin of BAM. Failure analysis and prevention is until today a central objective of our institute; due to its complex nature an interdisciplinary task. In our talk we will present an overview of the activities of BAM in the area of failure analysis and prevention; especial attention will be given to the VDI Guide 3822.
Die Grundlagen der Metallographie wurden in der zweiten Hälfte des 19. Jahrhunderts von Henry Clifton Sorby in England und Adolf Martens in Deutschland gelegt. Den verfügbaren Quellen nach erfolgten diese Arbeiten unabhängig voneinander. In diesem Beitrag werden die Beiträge von Adolf Martens und Emil Heyn zur Etablierung der Metallographie als ein eigenständiges Fach im Rahmen der Metallkunde dargestellt. Dabei werden Aspekte der Werkstoffprüfung, der Fraktographie und der Schadensanalyse einbezogen. Abschließend wird die führende Rolle dieser Pioniere der Metallkunde bei der Gründung der Deutschen Gesellschaft für Materialkunde (DGM) sowie des Deutschen Verbands für Materialforschung und -prüfung (DVM) gewürdigt.
In the present study, samples fabricated by varying the deposition hatch length during selective laser melting of nickel based superalloy Inconel 718 were investigated. Microstructure and texture of these samples was characterized using scanning electron microscopy, combined with electron back-scattered diffraction, and residual stress assessment, using neutron diffraction method. Textured columnar grains oriented along the sample building direction were observed in the shorter hatch length processed sample. A ten-fold increase in the hatch length reduced the texture intensity by a factor of two attributed to the formation of finer grains in the longer hatch length sample. Larger gradients of transverse residual stress in the longer hatch length sample were also observed. Along the build direction, compressive stresses in the shorter hatch length and negligible stresses for the longer hatch length specimen were observed. Changes to the temperature gradient (G) in response to the hatch length variation, influenced the G to growth rate (R) ratio and the product G × R, in agreement with the microstructures and textures formed. For the residual stress development, geometry of the part also played an important role. In summary, tailored isotropy could be induced in Inconel 718 by a careful selection of parameters during selective laser melting.