Observation of Dislocations Configuration of TiAl Alloy during Fatigue Tests at Elevated Temperatures

Abstract:

Isothermal fatigue (IF) tests were carried out on the gamma-TiAl alloy in the temperature of 500°C, 650°C and 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 dislocations configurations were also observed by TEM. The mechanism of cyclic hardening or softening during IF tests was also discussed. Results show that during the IF tests, The hysteresis loops were almost symmetrical above 600 °C, such as 650 °C and 800 °C; The hysteresis loops at the temperature of 500 °C generated two apparent asymmetry, one was zero asymmetry, the other was tensile and compressive asymmetry; Dislocation configuration and slip behaviors are contributed to cyclic hardening or cyclic softening.

• Periodical: Advanced Materials Research (Volumes 468-471)
• Pages: 2193-2200
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.468-471.2193
• Online since: February 2012
• Authors: Hong Fu Xiang, An Lun Dai, Hui Li, S.X. Li, Yu You Cui, Rui Rang
• Keywords: Cyclic Stress-Strain Response, Dislocation Configuration, Hysteresis Loop, Isothermal Fatigue, Titanium Aluminium Alloy

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