@article{OchsWehnertKnoppetal., author = {Ochs, Dennis and Wehnert, Kira-Kristin and Knopp, Kevin and Hartmann, J{\"u}rgen and Versch, Alexander and Schiffler, Andreas}, title = {Untersuchungen zur Temperaturleitf{\"a}higkeit additiv gefertigter Stahlproben in Abh{\"a}ngigkeit der relativen Dichte}, series = {FHWS Science Journal}, volume = {5}, journal = {FHWS Science Journal}, number = {2}, issn = {2196-6095}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:863-opus-19986}, pages = {75 -- 82}, abstract = {Das direkte Metall-Laser-Schmelzen (DMLS) aus der Familie der Additiven Fertigungsverfahren (AM) erm{\"o}glicht die schichtweise Erzeugung komplexer dreidimensionaler Geometrien mit hoher relativer Dichte unter Verwendung von Metallpulver als Ausgangsmaterial [1]. Die Technologie wird zunehmend eingesetzt, um innovative Bauteile material- und gewichtssparend herzustellen oder komplexe Produkte ohne zus{\"a}tzliche Werkzeuge oder Spannvorrichtungen zu fertigen. Dar{\"u}ber hinaus sind Funktionsintegrationen, zum Beispiel Gussformen mit eingepr{\"a}gten K{\"u}hlkan{\"a}len, m{\"o}glich. Da einzelne Metallpulverschichten auf vorhergehende Schichten aufgeschmolzen werden, entstehen w{\"a}hrend der Herstellung des Bauteils komplexe, zeitabh{\"a}ngige Temperaturprofile [2]. Durch den Einsatz hoher Laserintensit{\"a}ten und Scangeschwindigkeiten, bei denen die Belichtungszeit der Laserbestrahlung im Bereich von Millisekunden liegt, werden zudem extrem hohe Aufheiz- und Abk{\"u}hlraten induziert, die zu einzigartigen Mikrostrukturen und Materialeigenschaften f{\"u}hren [3]. Diese extremen Prozessbedingungen k{\"o}nnen sich jedoch auch negativ auf den Fertigungsprozess auswirken. Bei komplexen Bauteilen bleibt die Prozessstabilit{\"a}t und Qualit{\"a}tssicherung Umfragen zufolge weiterhin die wichtigste technologische Barriere f{\"u}r den Einsatz additiv gefertigter Bauteile in hochbelasteten oder sicherheitsrelevanten Bereichen [4]. Daher verspricht der Zusammenhang zwischen Temperaturprofil w{\"a}hrend der Fertigung, relativer Dichte der Bauteile, sowie thermophysikalischer Eigenschaften additiv gefertigter Proben wichtige Erkenntnisse, insbesondere im Hinblick auf eine zerst{\"o}rungsfreie Qualit{\"a}tssicherung, sowie neue Anwendungsm{\"o}glichkeiten.}, language = {de} } @article{JuergenArduiniManaraetal., author = {J{\"u}rgen, Hartmann and Arduini, Mariacarla and Manara, Jochen and Stark, Thomas and Ebert, Hans-Peter}, title = {Development and Evaluation of an Improved Apparatus for Measuring the Emissivity at High Temperatures}, series = {Sensors}, volume = {21}, journal = {Sensors}, number = {18}, issn = {1424-8220}, doi = {10.3390/s21186252}, abstract = {An improved apparatus for measuring the spectral directional emissivity in the wavelength range between 1 µm and 20 µm at temperatures up to 2400 K is presented in this paper. As a heating unit an inductor is used to warm up the specimen, as well as the blackbody reference to the specified temperatures. The heating unit is placed in a double-walled vacuum vessel. A defined temperature, as well as a homogenous temperature distribution of the whole surrounding is ensured by a heat transfer fluid flowing through the gap of the double-walled vessel. Additionally, the surrounding is coated with a high-emitting paint and serves as blackbody-like surrounding to ensure defined boundary conditions. For measuring the spectral directional emissivity at different emission angles, a movable mirror is installed in front of the specimen, which can be adjusted by a rotatable arrangement guiding the emitted radiation into the attached FTIR-spectrometer. The setup of the emissivity measurement apparatus (EMMA) and the measurement procedure are introduced, and the derived measurement results are presented. For evaluating the apparatus, measurements were performed on different materials. The determined emissivities agree well with values published in literature within the derived relative uncertainties below 4\% for most wavelengths.}, language = {en} } @article{HartmannLitorjaFowleretal., author = {Hartmann, J{\"u}rgen and Litorja, M. and Fowler, J. and Fox, N. and Stock, M. and Razet, A. and Khlevnoy, B. and Ikonen, E. and Machacs, M. and Doytchinov, K.}, title = {Final report on the CCPR-S2 supplementary comparison of area measurements of apertures for radiometry}, series = {Metrologia}, volume = {44}, journal = {Metrologia}, number = {02002}, language = {en} } @article{HartmannMoritzRothetal., author = {Hartmann, J{\"u}rgen and Moritz, W. and Roth, U. and Heyde, M. and Rademann, K. and Reichling, M.}, title = {Submicrosecond range surface heating and temperature measurement for efficient sensor reactivation}, series = {Thin Solid Films}, journal = {Thin Solid Films}, number = {391}, pages = {143 -- 148}, language = {en} } @inproceedings{HartmannDobhanEngelmannetal., author = {Hartmann, J{\"u}rgen and Dobhan, Alexander and Engelmann, Bastian and Eberhardt, Lars and Heusinger, Moritz and Raab, C and Schleif, Frank-Michael and T{\"u}rk, M.}, title = {Optimierung von Prozessen und Werkzeugmaschinen durch Bereitstellung, Analyse und Soll-Ist-Vergleich von Produktionsdaten: Digitalkonferenz}, language = {en} } @article{HartmannThuillierFoujolsetal., author = {Hartmann, J{\"u}rgen and Thuillier, G. and Foujols, T. and Bols{\´e}e, D. and Gillotay, D. and Hers{\´e}, M. and Petermanns, W. and Decupyer, W. and Mandel, H. and Sperfeld, P. and Taubert, Dieter Richard}, title = {SOLAR/SOLSPEC}, series = {Solar Physics}, journal = {Solar Physics}, number = {257}, pages = {185 -- 213}, language = {en} } @article{HartmannAnhaltLoweetal., author = {Hartmann, J{\"u}rgen and Anhalt, Klaus and Lowe, D. and Machin, Graham and Sadli, M. and Yamada, Y.}, title = {Thermodynamic temperature determinations of Co-C, Pd-C Pt-C and Ru-C eutectic fixed-points cells}, series = {Metrologia}, volume = {43}, journal = {Metrologia}, number = {2}, pages = {78 -- 83}, language = {en} } @article{HartmannMachinBloembergenetal., author = {Hartmann, J{\"u}rgen and Machin, G. and Bloembergen, P. and Sadli, M. and Yamada, Y.}, title = {A concerted international project to establish high-temperature fixed-points for primary thermometry}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {28}, pages = {1976 -- 1982}, language = {en} } @incollection{HartmannReichling, author = {Hartmann, J{\"u}rgen and Reichling, M.}, title = {Thermal transport in diamond}, series = {Properties and growth of diamond}, booktitle = {Properties and growth of diamond}, editor = {Nazar{\´e}, H. and Neves, A.J.}, publisher = {Institution of Electrical Engineers}, address = {London}, language = {en} } @article{HartmannSadliAnhaltetal., author = {Hartmann, J{\"u}rgen and Sadli, M. and Anhalt, Klaus and Schiller, S.}, title = {Thermal effects in the BB3200pg on M-C eutectic implementation}, series = {International Journal of Thermophysics}, journal = {International Journal of Thermophysics}, number = {30}, pages = {69 -- 76}, language = {en} }