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-48 Al-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 Δε_t. Meanwhile, the analysis of deformation substructure indicates that the corresponding deformation mechanisms are also dependent on Δε_t values. Deformation twinning prevails at high Δε_t 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.