Gamma titanium aluminide, TNB

Influence of Impact on the Mechanical Behaviour of the Gamma‐Based TiAl Alloy TNBV3B

“…An average value of 14 MPa(m) 1/2 AE 1 MPa(m) 1/2 for the fracture toughness of the cast material has been determined on the basis of the LEFM procedure described before making use of the results of ten impacted specimens from which six fulfilled the requirements. The fracture toughness values are in good agreement with literature data for TiAl alloys [1,2,20] reporting a fracture toughness between 10 and 16 MPa(m) 1/2 for duplex alloys. These results indicate that the influence of the damage after an impact event on the tensile behavior can be described using a LEFM analysis in the case of a random star-like crack network even though the crack geometry is not ideal and stable crack growth is neglected.…”

“…[1] The low ductility and fracture toughness result in a limited damage tolerance and a reduction of the fatigue life after impact damage. Nevertheless, titanium aluminides are very promising candidates for high-temperature applications in gas turbine engines due to their advantageous properties such as temperature capability and specific weight.…”

Scale composition and oxidation mechanism of the Ti–46Al–8Nb alloy in air at 700 and 800 °C

“…The major advantage of titanium aluminides compared with the state-of-the-art superalloys is low density (3.8e4.0 mg/cm 2 ) which might bring about up to 50% reduction of the device component mass [8]. Moreover, TiAl alloys have good dimensional stability and sufficient ductility at the service temperature, and may find application in a wide range of components, such as turbine blades, aero engine parts [9] or turbocharger rotors [10,11]. The major shortcomings of those alloys are: low ductility at room temperature, low fracture toughness [12], insufficient oxidation resistance at temperature exceeding 800 C [13] and solubility of small atoms, such as oxygen, nitrogen, hydrogen or carbon [14].…”

Microstructural instability and embrittlement behaviour of an Al-lean, high-Nb γ-TiAl-based alloy subjected to a long-term thermal exposure in air

“…Particularly, high-Nb-containing TiAl alloys and components are being developed [7][8][9][10][11][12][13] and manufactured [14][15][16][17][18]. A high level of Nb added would cause b phase to be retained since Nb is recognised to be a b phase stabiliser [19][20][21].…”