中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 20 No. 11 November 2010 |
thermo-mechanical fatigue tests
（1. Provincial Key Laboratory of Advanced Welding Technology,
Jiangsu University of Science and Technology, Zhenjiang 212003, China;
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:Thermo-mechanical fatigue tests were carried out on the gamma-TiAl alloy in the temperature range of 500−800 °C under mechanical strain control in order to evaluate its cyclic deformation behaviors at elevated temperature. Cyclic deformation curves, stress−strain hysteresis loops under different temperature−strain cycles were analyzed and dislocation configurations were also observed by TEM. The mechanisms of cyclic hardening or softening during thermo-mechanical fatigue (TMF) tests were also discussed. Results showed that thermo-mechanical fatigue lives largely depended on the applied mechanical strain amplitudes, applied types of strain and temperature. On the hysteresis loops appeared two apparent asymmetries: one was zero asymmetry and the other was tensile and compressive asymmetry. Dislocations configuration and slip behaviors were contributed to cyclic hardening or cyclic softening.
Key words: titanium-aluminium alloy; thermo-mechanical fatigue; cyclic stress response; hysteresis loop; dislocation
