Cyclic deformation of a modern TiAl alloy at high temperatures

0434491 - ÚFM 2015 RIV CH eng C - Konferenční příspěvek (zahraniční konf.)
Kruml, Tomáš - Chlupová, Alice - Obrtlík, Karel
Cyclic deformation of a modern TiAl alloy at high temperatures.
11th International Fatigue Congress. Zurich: Trans Tech Publications, 2014 - (Clark, G.; Wang, C.), s. 1131-1136. Advanced Materials Research, 891-892. ISBN 978-3-03835-008-8. ISSN 1022-6680.
[Fatigue 2014 - International Fatigue Congress /11./. Melbourne (AU), 02.03.2014-07.03.2014]
Grant CEP: GA MŠMT(CZ) ED1.1.00/02.0068; GA ČR(CZ) GAP107/11/0704
Institucionální podpora: RVO:68081723
Klíčová slova: low cycle fatigue * high temperature fatigue * dislocations * microstructure * lamellar TiAl alloy
Kód oboru RIV: JL - Únava materiálu a lomová mechanika

Ternary TiAl alloy with 8 at.% Nb and lamellar microstructure is subjected to low cycle fatigue tests at temperatures ranging from room temperature to 800 °C. The aim of the study is to find limit conditions when the microstructure is still stable and to study mechanisms of microstructural degradation when this limit is exceeded. Up to 750 °C, no cyclic softening or hardening is observed and cyclic stress-strain curve follows the tensile curve. Cyclic softening is characteristic for 800 °C. The TEM observation did not reveal any substantial changes in the microstructure due to the cycling up to 700°C. The lamellar structure is altered by cyclic straining at 750 °C and, to a higher extent, at 800°C. In specimens cycled to fracture at 800 °C, the domains without lamellar structure cover about 10% of volume and are almost dislocation free. The destruction of lamellar microstructure is the reason for the marked cyclic softening at 800 °C.
Trvalý link: http://hdl.handle.net/11104/0238646