Application of TiAl in a Turbocharger for Passenger Vehicles

Alloys based on γ-TiAl phase (hereafter TiAl) can be thought of as intermediate between ceramics and heat-resistant alloys. The greatest merit of TiAl is excellent high-temperature strength in spite of its light weight (specific gravity of 4) while its chief disadvantage is brittleness. Accordingly, a rotating component in which applied stress is in proportion to weight is the most suitable application. Furthermore, in cases where weight reduction directly improves equipment performance, the disadvantage of TiAl should be compensated. This report describes the first commercial application of TiAl in a turbocharger for passenger vehicles.