| Title |
Effects of lamellar Structure on the fatigue crack propagation of the fully lamellar gamm-TiAl alloys |
| Authors |
최철(Cheol Choi) ; 이용태(Yong Tai Lee) ; 이종수(Chong Soo Lee) |
| Abstract |
A study has been made to investigate the effects of colony size and lamellar spacing on the fatigue crack propagation behavior of the fully lamellar γ-TiAl alloys. The results show that the overall crack growth rates of the fully lamellar microstructure are not largely affected by the variation of the colony size, though its respective roles on the intrinsic and extrinsic nature are quite different. On the other hand, the lamellar spacing is proved to be the more important factor to control the fatigue resistance. The fine lamellar spacing microstructure represents superior fatigue crack growth resistance as compared to the coarse lamellar spacing microstructure, which is mainly attributed to the higher intrinsic nature of the microstructure as well as the higher extrinsic closure effects. The colony boundaries and the lamellar interface play an important role in retarding the advancing crack, serving as barriers for the dislocation movement and as sinks for dislocation pile-ups. |