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Title: Strengthening by intermetallic nanoprecipitation in Fe–Cr–Al–Ti alloy

In this paper, the strengthening mechanism observed during ageing at temperatures of 435 and 475 °C in the oxide dispersion strengthened (ODS) Fe–Cr–Al–Ti system has been investigated. Atom probe tomography (APT) and high-resolution transmission electron microscopy (HRTEM) analyses determined that the alloy undergoes simultaneous precipitation of Cr-rich (α' phase) and nanoscale precipitation of TiAl-rich intermetallic particles (β' phase). APT indicated that the composition of the intermetallic β' phase is Fe2AlTi0.6Cr0.4, and the evolving composition of α' phase with ageing time was also determined. The results obtained from HRTEM analyses allow us to confirm that the β' precipitates exhibit a cubic structure and hence their crystallography is related to the Heusler-type Fe2AlTi (L21) structure. Finally, the strengthening could be explained on the basis of two hardening effects that occur simultaneously: the first is due to the α-α' phase separation through the modulus effect, and the second mechanism is due to the interaction of nanoscale β' particles with dislocations.
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Spanish National Research Council (CSIC), Madrid (Spain). National Center for Metallurgical Research (CENIM). MATERALIA Group
  2. Univ. Complutense Madrid (Spain). National Center for Electron Microscopy (CNME)
  3. Univ. of Navarra, San Sebastian (Spain). CEIT and Tecnun
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 107; Journal ID: ISSN 1359-6454
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE Phase separation; Ferrous alloy; Mechanical alloying; Atom probe tomography; Thermoelectric power; Spinodal decomposition