High Temperature Deformation of a Nb-Ti-Al Alloy With σ+γ Microstructure

Abstract

AbstractAn alloy with composition 27Nb-33Ti-40Al (at. %) was heat treated to produce a fine two-phase microstructure of σ (Nb2Al) and γ (TiAl) phases. This microstructure exhibited a peak in the flow curves obtained in the strain rate range 5 × 10−4 to 5 × 10−6s−1 at 1000°C, with a stress exponent of 3. The deformation occurred by dislocation activity and twinning accompanied by dynamic recrystallization of the γ-phase and extensive grain boundary sliding of the σ-phase, which resulted in the separation and fragmentation of the latter phase.