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The role of nitrogen in the oxidation behaviour of a Ti6242S alloy: a nanoscale investigation by atom probe tomography

Dupressoire, Charlotte and Descoins, Marion and Vande Put, Aurélie and Epifano, Enrica and Mangelinck, Dominique and Emile, Philippe and Monceau, Daniel The role of nitrogen in the oxidation behaviour of a Ti6242S alloy: a nanoscale investigation by atom probe tomography. (2021) Acta Materialia, 216. 117134. ISSN 1359-6454

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Official URL: https://doi.org/10.1016/j.actamat.2021.117134

Abstract

When used at high temperature in air, titanium-based alloys form an oxide scale at their surface but also dissolve large amount of oxygen in their metallic matrix and this is a cause of embrittlement. Nitrogen is a secondary oxidant, which also dissolves in and embrittles the alloy. Oxidation experiments of Ti- 6Al-2Sn-4Zr-2Mo-0.1Si titanium-based alloy, for 10 0 0 h at 650 °C in synthetic air (N 2 -20%O 2 ) and in a mixture of Ar-20%O 2 , showed that nitrogen decreases both oxide scale growth and oxygen dissolution. Atom probe tomography was used to investigate the alloy/oxide interface. The results revealed that the nitrogen effect is due to the formation of interfacial layers of oxynitrides and nitride (Ti 2 N), but also to the formation of a nitrogen rich α-titanium-based solid solution, which all act as diffusion barriers for oxygen, because of their low oxygen solubility. A comparison between the experimental results and thermodynamic calculations is also reported.

Item Type:Article
HAL Id:hal-03431660
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Aix-Marseille Université - AMU (FRANCE)
Other partners > Airbus (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Université de Toulon - UTLN (FRANCE)
Laboratory name:
Funders:
Agence Nationale de la Recherche - ANR - CNRS-CEA
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Deposited On:16 Nov 2021 17:32

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