On the Influence of Thermomechanical Processing on the Fatigue and Fracture Behavior of Gamma-Based Titanium Aluminides. IV. Effects of Alloying with V

ABSTRACT

The effects or microstructure on the room - and elevated-temperature tensile and fracture properties of Ti-48Al-2.2V and Ti-48AI-3V are discussed in this paper, Microstructure is controlled by extrusion with different reduction ratios (10:1 and 14:1) and annealing in the α + γ and α₂ + γ phase fields. V-containing Ti-48Al base alloys are shown to have attractive combinations of tensile and fracture properties only in the asextruded conditions. However, their tensile and fracture properties are degraded severely upon thermal exposure, which also results in grain boundary precipitation and fast microstructural transformations from nearly lamellar to nearly equiaxed structures. The degree of degradation is shown to increase with increasing V content and annealing duration. V-containing Ti-48Al base alloys are shown to have very limited potential for future alloy development.