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Title: In situ neutron diffraction in quantifying deformation behaviors of nano-sized carbide strengthened UFG ferritic steel

Here, the microstructures and mechanical properties of a low-alloy medium-carbon steel with a duplex microstructure composed of nanoscale spheroidized carbides in ultrafine-grained (UFG) ferritic steel are examined. The average grain size of the studied steel is ~ 430 nm, and these grains coexist with numerous carbides. Neutron diffraction reveals that the intensity of (011) and (022) peaks for the UFG sample is significantly enhanced, suggesting that the (011)//RD texture is a result of the warm rolling process. The lattice parameter of UFG steel is smaller than that of a martensitic steel (M steel) counterpart, indicating a lower carbon concentration in the lattice. The estimated dislocation densities for M steel and UFG steel are 2.59 × 10 14 cm –2 and 1.76 × 10 12 cm –2, respectively. The UFG steel reveals a nearly isotropic lattice strain response under initial tension from 0 to 450 MPa, where the lattice strains of the (110), (002), and (112) planes are identical. The increase of lattice strain of the (110) plane becomes smaller than that of the (002) and (112) planes as the stress exceeds 450 MPa, suggesting that the nanosized carbides contribute to the hardening ability by promoting the accumulation of geometrically necessarymore » dislocations around the particles, and the (110) lattice becomes harder compared to the other two planes.« less
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  1. Northeastern Univ., Shenyang (China)
  2. Chinese Academy of Engineering Physics, Mianyang (China)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing
Additional Journal Information:
Journal Volume: 726; Journal Issue: C; Journal ID: ISSN 0921-5093
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; Ultrafine-grained ferritic steel; Nanosized carbides; Strength; Neutron diffraction
OSTI Identifier: