Investigation of Crack Growth in Titanium-Aluminide at Elevated Temperatures

摘要

This study investigates crack growth at elevated temperatures in a titanium-aluminide alloy (Ti3Al). The objectives are to determine the creep crack growth characteristics and the applicability of linear cumulative damage modeling to Ti3Al alloy. All tests were conducted on compact tension specimens of Ti3Al under isothermal conditions. Sustained load tests were used to characterize creep crack growth behavior. A fatigue test and several hold-time tests were used to test the applicability of linear cumulative damage modeling. The linear elastic stress intensity factor, K, was used a correlating parameter for all the tests. A model was generated using baseline data from the sustained load and fatigue tests and compared with the hold-time tests. The test results showed that sustained load crack growth is insensitive to temperature. Crack growth rates for all tested temperatures were only a factor of five apart between the slowest and fastest growth rates. Keywords: Creep, Fatigue, Crack propagation, Titanium aluminide, Damage modeling, Thesis. (jes)