Cyclic deformation mechanisms in a gamma titanium aluminide alloy at room temperature

This paper presents experimental results on the room temperature cyclic stress-strain (CSS) behaviour of a quaternary Ti-48Al-2Cr-2Nb (at.%) alloy produced by casting and powder metallurgy and TEM observations of the corresponding deformation mechanisms. The CSS behaviour is strongly dependent on the applied total strain amplitude Δεt. Meanwhile, the analysis of deformation substructure indicates that the corresponding deformation mechanisms are also dependent on Δεt values. Deformation twinning prevails at high Δεt values where a pronounced continuous hardening is observed, while the moderate hardening observed at lower values corresponds to deformation by dislocation glide, leading to the formation of a vein-like structure.