TY - CONF A1 - von Hartrott, P. A1 - Rockenhäuser, Christian A1 - Schriever, Sina A1 - Metzger, M. A1 - Skrotzki, Birgit T1 - Correlation of the precipitate size evolution and the creep rate of the aluminum alloy EN AW 2618A at 190 °C N2 - Ther results of research on correlation of precipitate size Evolution and the creep rate of the Aluminium alloy EN AW 2618A at 190 °C was presented. T2 - ICAA16 CY - Montreal, Canada DA - 17.06.2018 KW - Alloy 2618A KW - Creep KW - Aluminium KW - Coarsening PY - 2018 AN - OPUS4-45283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Epishin, A. A1 - Nolze, Gert A1 - Schriever, Sina A1 - Feldmann, Titus A1 - Ijaz, M. A1 - Viguier, B. A1 - Poquillon, D. A1 - Le Bouar, Y. A1 - Ruffini, A. A1 - Finel, A. T1 - Creep of single-crystals of nickel-base superalloys at ultra-high homologous temperature N2 - The creep behavior of single-crystals of the nickel-base superalloy CMSX-4 was investigated at 1288°C, which is the temperature of the hot isostatic pressing (HIP) treatment applied to this superalloy in the industry. It was found that at this super-solvus temperature, where no Gamma’-strengthening occurs, the superalloy is very soft and rapidly deforms under stresses between 4 and 16 MPa. The creep resistance was found to be very anisotropic, e.g. the creep rate of [001] crystals was about 11 times higher than that of a [111] crystal. The specimens of different orientations also showed a very different necking behavior. The reduction of the cross-section area psi of [001] crystals reached nearly 100%, while for a [111] crystal psi=62%. The EBSD analysis of deformed specimens showed that despite such a large local strain the [001] crystals didn’t not recrystallize, while a less deformed [111] crystal totally recrystallized within the necking zone. From the shape of deformed specimens and TEM investigations it was concluded that the main strain contribution resulted from <011> {111} octahedral slip. T2 - EuroSuperalloys 2018 CY - Oxford, UK DA - 09.09.2018 KW - Nickel-base superalloys KW - Single-crystals KW - Creep PY - 2018 AN - OPUS4-45989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Czediwoda, Fabian A1 - Fedelich, Bernard A1 - Stöhr, B. A1 - Göhler, T. A1 - Völkl, R. A1 - Nolze, Gert A1 - Glatzel, U. T1 - A numerical approach to model high-temperature creep behaviour of Ni-base superalloys from microstructural morphology to grain size scales N2 - A constitutive model for the mechanical behaviour of single crystal Ni-base superalloys under high temperature conditions has been developed in the framework of a Cooretec project in cooperation with Siemens AG, MTU Aero Engines AG and University Bayreuth. In addition to the conventional material properties e.g. elastic constants, the model requires the parameters of the initial microstructure as an input. Thus, the γ’-precipitate size and the channel width of the γ-matrix were obtained from SEM micrographs. The model uses the slip system theory and describes the movement, multiplication and annihilation of dislocations in the channels. Furthermore, the cutting of precipitates is another mechanism contributing to the plastic flow. The evolution of the morphology due to rafting and its effects on the deformation have been implemented according to. The kinematic hardening is introduced as a stress tensor to realistically represent the strain hardening of arbitrary oriented single crystals. The mechanical behaviour of single crystal specimens has been experimentally investigated in tension tests at different strain rates and in creep tests under various loads. The constitutive model has been calibrated based on the experimental data for temperatures of 950°C and 850°C and the [001] and [111] crystallographic orientations. Finally, a micromechanical model was created to simulate the creep response of additive manufactured polycrystalline structures. An EBSD image is taken to obtain the grain geometry and their respective orientation. The grain boundaries are discretised using cohesive elements, whereas the single crystal model was applied to each grain in the representative volume. The polycrystal model is generated using Dream3D, NetGen and other software previously developed at the BAM. T2 - 6th European Conference on Computational Mechanics (ECCM 6) CY - Glasgow, UK DA - 11.06.2018 KW - Nickel-base superalloy KW - Creep KW - Rafting KW - Viscoplasticity KW - EBSD KW - Grain boundaries PY - 2018 AN - OPUS4-46973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -