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

When used at high temperature in air, titanium-based alloys form an oxide scale their surface but also dissolve large amount of oxygen metallic matrix and this is a cause embrittlement. Nitrogen secondary oxidant, which dissolves embrittles the alloy. Oxidation experiments Ti-6Al-2Sn-4Zr-2Mo-0.1Si alloy, for 1000 h 650 °C synthetic air (N2-20%O2) mixture Ar-20%O2, showed that nitrogen decreases both growth dissolution. Atom probe tomography was to investigate alloy/oxide interface. The results revealed effect due formation interfacial layers oxynitrides nitride (Ti2N), rich ?-titanium-based solid solution, all act as diffusion barriers oxygen, because low solubility. A comparison between experimental thermodynamic calculations reported.