Development and evaluation of TiAl sheet structures for hypersonic applications

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 464; no. 1; pp. 330 - 342
• Main Authors: Draper, S.L., Krause, D., Lerch, B., Locci, I.E., Doehnert, B., Nigam, R., Das, G., Sickles, P., Tabernig, B., Reger, N., Rissbacher, K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25.08.2007; Elsevier
• Subjects: Applications; Applied sciences; Elasticity. Plasticity; Engineering techniques in metallurgy. Applications. Other aspects; Exact sciences and technology; Fabrication; Fatigue; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Sheet; Titanium aluminide; Fabrication; Mechanical properties; Sheet; Titanium aluminide; Titanium alloy; Scanning electron microscopy; Creep test; Hypersound; Transition metal; Aluminium alloy; High temperature; Aeronautic industry; Tension test; Fatigue test; Transition metal alloy; Sheet metal; Application
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2007.02.020

A cooperative program between the National Aeronautics and Space Administration (NASA), the Austrian Space Agency (ASA), Pratt & Whitney, Engineering Evaluation and Design, and Plansee AG was undertaken to determine the feasibility of achieving significant weight reduction of hypersonic propulsion system structures through the utilization of TiAl. A trade study defined the weight reduction potential of TiAl technologies as 25–35% compared to the baseline Ni-base superalloy for a stiffener structure in an inlet, combustor, and nozzle section of a hypersonic scramjet engine. A scramjet engine inlet cowl flap was designed, along with a representative subelement, using design practices unique to TiAl. A subelement was fabricated and tested to assess fabricability and structural performance and validate the design system. The TiAl alloy selected was PLANSEE's third generation alloy Gamma Met PX, 1 1 Gamma Met PX is a trademark of PLANSEE AG, Austria. a high temperature, high-strength γ-TiAl alloy with high Nb content. Characterization of Gamma Met PX sheet, including tensile, creep, and fatigue testing was performed. Additionally, design-specific coupons were fabricated and tested in order to improve subelement test predictions. Based on the sheet characterization and results of the coupon tests, the subelement failure location and failure load were accurately predicted.