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 te...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.展开更多
基金Project (2008CL068L) supported by the Natural Science Research Project of Higher Education of Jiangsu Province, ChinaProject (50901036) supported by the National Natural Science Foundation of China
基金Project(SBK200930307) supported by Natural Science Foundation of Jiangsu Province,China
文摘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.
