TiAl-Based Intermetallics for Turbine Applications—Status, Development Opportunities and Challenges

Titanium-based intermetallic alloys have been for years identified as a solution for weight reduction in turbo-engine. The improved specific mechanical properties of these alloys, when compared to Ni-based superalloys, have pushed Safran and other major aero-turbine producers to develop and to introduce them in their newest generations of turbines. Nevertheless, despite clear advantages, not all of them are a reality for mass production.<br/>In the present study, the case of TiAl intermetallic systems will be used to exemplify actual developments, applications and remaining challenges for a widespread industrial usage of such alloys.<br/>The industrialization steps for TiAl alloys in actual aircraft engines will clarify the importance of choosing adapted processing routes for complex parts production, and its strong interlinking with final properties and design. A specific section will focus on new Powder Metallurgy routes and their application to industrial parts.<br/>In particular, the latest development of the Spark Plasma Sintering process to produce complex part out of TiAl powders will be detailed. The impact of the process parameters on final properties, as well as composition of alloys on microstructure will be discussed and compared to actual mechanical properties. An analysis of energy consumption will be presented with the comparison of such new processed with regard to conventional ones.<br/>A discussion will be open as well to specifically address the issue of impact tolerance for such alloys, and particularly when targeting the next generation of engines.