The fatigue crack propagation resistance of a lamellar TiAl-alloy has been investigated. It has been proved to be slightly influenced by temperature in air and in vacuum, suggesting that the effect of the Ductile-Brittle Transition is not highly pronounced. Fractographic observations supported this point. Crack closure has been shown to play a significant role whatever the temperature. However, the influence of oxide4nduced closure is reduced even at 750 and 800°C. Finally, fatigue cracks propagate much faster in air than in vacuum at all temperatures. Details concerning the embrittling mechanisms at room and elevated temperature are discussed.
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