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Title: In Situ Synchrotron Tensile Investigations on 14YWT, MA957 and 9-Cr ODS Alloys

Nanostructured ferritic alloys (NFAs) provide exceptional radiation tolerance and high-temperature mechanical properties when compared to traditional ferritic and ferritic/martensitic (F/M) steels. Their remarkable properties result from ultrahigh density and ultrafine size of Y-Ti-O nanoclusters within the ferritic matrix. In this work, we applied a high-energy synchrotron radiation X-ray to study the deformation process of two NFAs including 14YWT and MA957, and a 9-Cr ODS steel. Only the relatively large nanoparticles in the 9-Cr ODS were observed in the synchrotron X-ray diffraction. The nanoclusters in both 14 YWT and MA957 were invisible in the measurement due to their non-stoichiometric nature. Due to the different sizes of nanoparticles and nanoclusters in the materials, the Orowan looping was considered to be the major strengthening mechanism in the 9-Cr ODS, while the dispersed-barrier-hardening is dominant strengthening mechanism in both 14YWT and MA957, respectively. This analysis was inferred from the different build-up rates of dislocation density when plastic deformation was initiated. Finally, the dislocation densities interpreted from the X-ray measurements were successfully modeled using the Bergstr m s dislocation models.
 [1] ;  [2] ;  [2] ;  [1] ;  [1] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [6] ;  [1] ;  [2]
  1. University of Illinois at Urbana-Champaign
  2. Argonne National Laboratory (ANL)
  3. Clemson University
  4. ORNL
  5. Argonne National Laboratory (ANL), Advanced Photon Source (APS)
  6. University of Science and Technology Beijing, China
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Resource Relation:
Conference: TMS 2015: 144th Annual Meeting and Exhibition, Orlando, FL, USA, 20150315, 20150319
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
Work for Others (WFO)
Country of Publication:
United States