Ti2AlNb-based intermetallic alloys and composites


Optimization of the chemical composition of Ti2AlNb-based alloy resulted in development of high-strength Ti-20.3Al-22.1Nb-1.2Zr-1.3V-0.9Mo-0.3Si (at.%) intermetallic with rather low density ρ≈5.1 g/cm3. Mechanical properties of the alloy were considerably improved due to formation of the homogeneous ultrafine-grained structure. The ultrafine-grained material exhibited both high strength and ductility at room temperature (σUTS=1400 MPa; δ=25%) and superplastic behavior in the temperature range of 850-1000°C (δmax=930% at T=900°C). The metal-intermetallic composites consisting of alternating layers of the orthorhombic intermetallic alloy and the commercial high-temperature titanium alloywere produced. The 3-layered composite had high strength and reasonable ductility both at room and elevated temperatures: σUTS=1235 MPa and δ=4% at T=20°C; σUTS=875 MPa and δ=21% at T=600°C.