TY - JOUR A1 - Brookes, Stephen-Peter A1 - Kühn, Hans-Joachim A1 - Skrotzki, Birgit A1 - Klingelhöffer, Hellmuth A1 - Sievert, Rainer A1 - Pfetzing, J. A1 - Peter, D. A1 - Eggeler, G. T1 - Axial-torsional thermomechanical fatigue of a near-gamma TiAl-alloy N2 - The uniaxial, torsional and axial-torsional thermomechanical fatigue (TMF) behavior of the near-γ TiAl-alloy TNB-V5 was investigated. TMF tests were performed at 400-800 °C with mechanical strain amplitudes ranging from 0.15% to 0.7%. The tests were conducted thermomechanically in-phase (IP) and out-of-phase (OP). For the same lifetimes, uniaxial IP tests required the highest strain amplitudes, while OP test conditions were most damaging and needed the lowest strain amplitudes. The Mises equivalent mechanical strain amplitudes of pure torsional tests were found in between uniaxial in-phase and out-of-phase tests for the same lifetimes. The non-proportional multiaxial out-of-phase test showed a lower lifetime at the same equivalent mechanical strain amplitude compared to the other types of tests. The microstructure has been characterized applying electron microscopy and microstructural parameters such as fraction of twinned grains, grain size, lamellar distance and dislocation density have been quantified. KW - Gamma titanium aluminide KW - TNB-V5 KW - Thermomechanical fatigue (TMF) KW - Axial-torsional loading KW - Microstructure PY - 2010 DO - https://doi.org/10.1016/j.msea.2010.03.073 SN - 0921-5093 SN - 1873-4936 VL - 527 IS - 16-17 SP - 3829 EP - 3839 PB - Elsevier CY - Amsterdam AN - OPUS4-21289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brookes, Stephen-Peter A1 - Kühn, Hans-Joachim A1 - Skrotzki, Birgit A1 - Klingelhöffer, Hellmuth A1 - Sievert, Rainer A1 - Pfetzing, J. A1 - Peter, D. A1 - Eggeler, G. T1 - Multi-Axial Thermo-Mechanical Fatigue Of A Near-Gamma TiAl-Alloy N2 - A material family to replace the current superalloys in aeronautical gas turbine engines is considered to be that of gamma Titanium Aluminide (γ-TiAl) alloys. Structural components in aeronautical gas turbine engines typically experience large variations in temperatures and multiaxial states of stress under non-isothermal conditions. The uniaxial, torsional and bi-axial thermomechanical fatigue (TMF) behaviour of this γ-TiAl alloy have been examined at 400 – 800°C with strain amplitudes from 0.15% to 0.7%. The tests were conducted at both in-phase (IP) and out-ofphase (OP). The effects of TMF on the microstructure were also investigated. For the same equivalent mechanical strain amplitude uniaxial IP tests showed significantly longer lifetimes than pure torsional TMF tests. The non-proportional multiaxial OP test showed the lowest lifetimes at the same equivalent mechanical strain amplitude compared to the other types of tests. KW - Gamma-Titanium Aluminide KW - Thermo-mechanical Fatigue KW - Axial-torsional Loading PY - 2005 DO - https://doi.org/10.4028/3-908454-01-8.283 SN - 1022-6680 SN - 1662-8985 VL - 59 SP - 283 EP - 287 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-18720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kühn, Hans-Joachim A1 - Kahlcke, Ole A1 - Brookes, Stephen-Peter T1 - A practicable nominal temperature tolerance for TMF-tests N2 - The aim of this research was to investigate the influence of nominal temperature errors on test results and to develop the nominal temperature tolerance for TMF-tests. This concept was confirmed with series of specially developed TMF-tests with defined temperature errors, performed on one test material (NIMONIC 90) in a temperature range of 400–850 °C. These tests should show the influence of temperature errors on test results with an emphasis on lifetime in comparison with reference tests. It is shown that with a limited number of specimens and only one test material, it is possible to propose a reasonable general temperature tolerance for TMF-tests, valid for a wide range of materials and test conditions. KW - Thermo-mechanical fatigue KW - Temperature tolerance KW - Temperature error KW - Life time PY - 2008 DO - https://doi.org/10.1016/j.ijfatigue.2007.01.057 SN - 0142-1123 VL - 30 IS - 2 SP - 277 EP - 285 PB - Elsevier CY - Oxford AN - OPUS4-16133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -