Positron annihilation characterization of nanostructured ferritic alloys

✍ Scribed by M.J. Alinger; S.C. Glade; B.D. Wirth; G.R. Odette; T. Toyama; Y. Nagai; M. Hasegawa

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 728 KB
• Volume: 518
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2009.04.040

✦ Synopsis

Nanostructured ferritic alloys (NFAs) were produced by mechanically alloying Fe-14Cr-3W-0.4Ti and 0.25Y 2 O 3 (wt%) powders followed by hot isostatic pressing consolidation at 850, 1000 and 1150 • C. Positron annihilation lifetime and orbital momentum spectroscopy measurements are in qualitative agreement with small angle neutron scattering, transmission electron microscopy and atom probe tomography observations, indicating that up to 50% of the annihilations occur at high densities of Y-Ti-O enriched nm-scale features (NFs). Some annihilations may also occur in small cavities. In Y-free control alloys, that do not contain NFs, positrons primarily annihilate in the Fe-Cr matrix and at features such as dislocations, while a small fraction annihilate in large cavities or Ar bubbles.