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Title: Tensile deformation and fracture properties of a 14YWT nanostructured ferritic alloy

Here, a new larger heat of a 14YWT nanostructured ferritic alloy (NFA), FCRD NFA-1, was synthesized by ball milling FeO and argon atomized Fe-14Cr-3W-0.4Ti-0.2Y (wt%) powders, followed by hot extrusion, annealing and cross rolling to produce an ≈10 mm-thick plate. NFA-1 contains a bimodal size distribution of pancake-shaped, mostly very fine scale, grains. The as-processed plate also contains a large population of microcracks running parallel to its broad surfaces. The small grains and large concentration of Y–Ti–O nano-oxides (NOs) result in high strength up to 800 °C. The uniform and total elongations range from ≈1–8%, and ≈10–24%, respectively. The strength decreases more rapidly above ≈400 °C and deformation transitions to largely viscoplastic creep by ≈600 °C. While the local fracture mechanism is generally ductile-dimple microvoid nucleation, growth and coalescence, perhaps the most notable feature of tensile deformation behavior of NFA-1 is the occurrence of periodic delamination, manifested as fissures on the fracture surfaces.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of California, Santa Barbara, CA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; FG03-94ER54275
Type:
Accepted Manuscript
Journal Name:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing
Additional Journal Information:
Journal Volume: 675; Journal Issue: C; Journal ID: ISSN 0921-5093
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; nanostructured ferritic alloy; nano oxide; delamination; tensile properties; fractography
OSTI Identifier:
1330546
Alternate Identifier(s):
OSTI ID: 1399033