The recently developed TiAl intermetallics-based alloys are promising candidate materials for high temperature applications in gas turbines. However, the mechanism of the creep rupture in TiAl alloys has not been well understood and the degradation of lamellar structure at high temperatures with/without loading has not been studied in a systematic manner. The key objectives of the proposed research are: (1) to gain an insight into the degradation mechanisms in TiAl creep specimens and (2) to explore ways to prevent the origination of lamellar degradation and to improve the creep resistance by increasing the lamellar stability.