Improving the oxidation resistance of γ-titanium aluminides by halogen treatment

✍ Scribed by A. Donchev; M. Schütze

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: German
• Weight: 325 KB
• Volume: 59
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.200804132

✦ Synopsis

Abstract

Intermetallic alloys based on TiAl are candidates for several structural high temperature applications but their oxidation resistance is limited to temperatures below 800 °C. In this paper the results of high temperature oxidation and creep tests will be presented and discussed. The treatment with halogens improves the oxidation resistance of these alloys up to 1050 °C. A thin protective Al~2~O~3~‐layer is formed after treatment with halogens instead of the mixed TiO~2~/Al~2~O~3~/TiN scale typically grown on these alloys. This alumina layer protects the component under isothermal and thermocyclic conditions. The protective effect is stable up to at least 8760 h. Creep tests of halogen treated materials at high temperatures showed no effect on the creep behaviour. Automotive turbocharger rotors were exposed at 1050 °C in air with and without fluorine‐treatment for demonstration of real parts.