Communication Dans Un Congrès Année : 2023

Compositional effects on the formation and thermal evolution of oxygen-ordered precipitates in Ti-Zr-O alloys: an in-situ synchrotron X-ray diffraction study

Résumé

Among the various significant questions affecting titanium metallurgy, the effect of interstitials, more specifically oxygen, on the (mechanical) properties of titanium alloys remain one of the most critical issues. According to a largely spread idea in the scientific community, small additions of oxygen induce a strong hardening effect resulting in a large increase in strength coupled with a drastic loss in ductility. This embrittlement has been interpreted, until now, as a consequence of the deformation localization initiated by the interaction between the dislocations and isolated oxygen atoms in solid solution. To prevent this ductility loss, many efforts have been made to inhibit oxygen diffusion during processing and thermal treatments of titanium alloys. On this basis, there are several key challenges in the development of new oxygen-tolerant titanium alloys that could take advantage of oxygen hardening without suffering from embrittlement. In that context, ternary Ti-Zr-O α-alloys have been developed, displaying oxygen and zirconium contents ranging from 0.15 to 0.8 and 0 to 9 (wt%) respectively. These materials have been shown to present nano-precipitates with a Ti6O-structure resulting from local ordering of oxygen in octahedral interstitial sites predicted by ab initio calculations. It is worth noting that this was the first time these precipitates were observed in structural alloys with such low oxygen contents. This work focuses on the characterization of the thermal stability and the compositional range of existence of the above-mentioned nano-precipitates. First point is studied thanks to in-situ thermal cycles realized with an induction furnace under neutral atmosphere coupled to DiffAbs beamline (SOLEIL synchrotron, France). As to the second item, the influence of the composition on the structure and the stability of the nano-precipitation is investigated by analyzing alloys with various oxygen and zirconium contents. Finally, the different perspectives and questions raised by these findings will be considered.

Domaines

Matériaux
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Dates et versions

cea-04596653 , version 1 (31-05-2024)

Identifiants

  • HAL Id : cea-04596653 , version 1

Citer

Raphaelle Guillou, Emmanuel Clouet, Jean-Luc Bechade, Dominique Thiaudière, Frédéric Prima, et al.. Compositional effects on the formation and thermal evolution of oxygen-ordered precipitates in Ti-Zr-O alloys: an in-situ synchrotron X-ray diffraction study. World Titanium Conference, Jun 2023, Edimbourg, United Kingdom. ⟨cea-04596653⟩
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