Ti-rich precipitate evolution in vanadium-based alloys during annealing above 400 °C

A. Impagnatiello, T. Toyama, E. Jimenez-Melero

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We have assessed the plate-like TiO precipitate evolution in V-4Ti and V-4Ti-4Cr alloys during isochronal annealing above 400 °C, by combining Vickers hardness, positron lifetime and coincidence Doppler broadening measurements. Our results reveal the formation of additional TiO precipitates in both alloys at temperatures of 450–600 °C in both alloys. The implanted positrons become trapped at the nm-thick TiO/matrix interface, and act as effective probes of the concomitant annealing of vacancies taking place inside the TiO precipitates above 550 °C in V-4Ti alloy. The presence of Cr in the ternary alloy not only retards the recovery of dislocations, but also enhances the oxygen diffusivity and therefore decreases the vacancy content in the TiO precipitates. These results will impact the expected alloy stability and capacity to bind light elements in the operational temperature window of these alloys for fusion reaction applications.

Original languageEnglish
Pages (from-to)122-128
Number of pages7
JournalJournal of Nuclear Materials
Volume485
DOIs
Publication statusPublished - 2017 Mar 1

Keywords

  • Crystalline oxides
  • Electron microscopy
  • Nuclear fusion reactor
  • Positron annihilation
  • Refractory metal

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Materials Science(all)
  • Nuclear Energy and Engineering

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