Article Dans Une Revue Acta Materialia Année : 2023

Effect of prior α 2 phase on precipitation kinetics of O-phase in advanced Ti2AlNb alloy

Widad Ayadh
Benoît Denand
Pascal Boulet
Mohamed Sennour
Jérôme Delfosse
Pierre Sallot

Résumé

To study the influence of prior α₂ phase on O-phase formation kinetics in β matrix, different isothermal heat treatments were performed at 876 and 780 °C using an advanced Ti2AlNb alloy with varying fraction of α₂ phase. The kinetics of phase transformations was followed by electric resistivity measurements coupled to multi-scale microstructure characterization using scanning and transmission electron microscopy, energy dispersive X-ray spectrometry (EDS) and quantitative X-ray diffraction. It is revealed that the effect of α₂ phase on the formation of O-phase depends on transformation temperature: while at 876 °C prior α₂ precipitates lead to significantly slower formation of O-phase, as compared to α₂ free alloy, the kinetics of O-phase formation is faster at 780 °C in the presence of α₂ phase. Using EDS data as well as accurate measurements of lattice parameter of β phase, the diffusion character of O-phase formation in β matrix with and without prior α₂ is shown for 876 °C while at 780 °C the diffusionless character of the O-phase formation is revealed for the beginning of the transformation followed by the partitioning of the alloying elements for prolonged treatment durations.

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Dates et versions

hal-04160996 , version 1 (13-07-2023)

Identifiants

Citer

Widad Ayadh, Benoît Denand, Ahmed Halkoum, Pascal Boulet, Mohamed Sennour, et al.. Effect of prior α 2 phase on precipitation kinetics of O-phase in advanced Ti2AlNb alloy. Acta Materialia, 2023, 252, pp.118930. ⟨10.1016/j.actamat.2023.118930⟩. ⟨hal-04160996⟩
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