Effect of Nb Content and Temperature on the TiN Formation During the Oxidation of Ti 3 Al

Nb addition to Ti 3 Al has been found to be effective to improve its oxidation resistance. Recently, the beneficial effect of nitrogen in the oxidation behaviour of Nb contained T 3 Al-based alloys has been noticed. In this paper, the oxidation behaviour of five alloys with different Nb content from 0 to 20 at. % exposed in room air at different temperatures (from 600 to 950, C) has been examined with the focus on the TiN formation in the oxide scale. No TiN is detected in the scales of binary Ti 3 Al under all temperatures tested. On the contrary, in alloys containing Nb, TiN is identified in the scales irrespective of the oxidation temperature. The amount of TiN formation differs with differentNb content. EPMA analysis of the cross section of the scales is performed and discussion is made accordingly.