Investigation of the Orientation Relationship between Massive Gamma Phase and Parent Alpha-2 Phase in a Two-Phase TiAl Alloy

摘要

Channelling patterns using backscattered electrons in SEM have been used to study the orientation relationship of massive transformed gamma phase and the alpha phase into which the massive phase is growing in a two-phase TiAl alloy. These patterns have not revealed the presence of a clear orientation relationship between massive gamma and the alpha-2 phase. In order to identify the mechanisms of the massive transformation, TEM observations have been carried out on the interface between massive gamma phase and alpha-2 matrix phase. The significance of these observations will be discussed in terms of the nature of the phase transformation and the structural stability of TiAl alloys.