TY - JOUR A1 - Wilhelm, Franz A1 - Affeldt, Ernst Eugen A1 - Fleischmann, Ernst W. A1 - Glatzel, U. A1 - Hammer, Joachim T1 - Modeling of the deformation behavior of single crystalline Nickel-based superalloys under thermal mechanical loading T2 - International Journal of Fatigue N2 - The focus of this paper is the simulation of the thermal-mechanical fatigue behavior (TMF) of two single crystalline Nickel-based superalloys in a temperature range between 400 degrees C and 980 degrees C. The newly developed rhenium-free alloy Astra-3OptW and the rhenium-free alloy CMSX-6 are analyzed concerning the basic deformation mechanisms, i.e. elasticity, time-independent and time-dependent plasticity contributing to hardening. In detail, the relevant parameters for high temperature deformation are identified from isothermal creep experiments and used in a numerical model to simulate the deformation behavior under instationary thermal and mechanical loading. Special attention is focused on the determination of the hardening by the second phase (gamma'-precipitates) and their influence on time-dependent deformation and relaxation mechanisms. Therefore, the parameters describing the stress and temperature dependence of the creep rate (i.e. stress exponent n and activation energy Q) are interpreted in terms of a threshold stress taking into account the hardening contribution of the gamma'-phase. Thus, only a reduced effective stress is active for plastic deformation. Particular attention is focused on the accurate determination of the threshold stress as a function of temperature and applied stress from the Langeborg-Bergmann-plot. The comparison of the simulated TMF-deformation to the experimental TMF-data clearly indicates the accuracy of the model in predicting the resulting stresses induced by instationary thermal and mechanical loading. (C) 2016 Elsevier Ltd. All rights reserved. KW - Creep KW - MICROSTRUCTURAL MODEL KW - Modeling KW - PARTICLES KW - Plasticity KW - Single crystalline Nickel-based superalloys KW - Thermal-mechanical fatigue KW - THERMOMECHANICAL FATIGUE KW - Threshold stress concept Y1 - 2017 UR - https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/3174 VL - 97 SP - 1 EP - 8 PB - Elsevier ER -