Evolution of Surface Morphology of Oxide Formed During Initial-Stage Oxidation of gamma-TiAl Alloy Using In Situ Environmental SEM

摘要

Initial-stage oxidation characteristics of a -TiAl alloy were investigated by using in situ environmental scanning electron microscopyfor both heating and isothermal oxidation processes. Selective oxidation led to primary nucleation and growth on thealuminum-rich phase. Under different isothermal oxidation times, the oxide morphology changed to a linear structure between 750 degrees C and 774 degrees C and to an acicular structure at 800 degrees C. The initial oxidation process of -TiAl alloy could be divided into three stages: nucleation; growth; and morphological transformation and subsequent growth stages.