Research ArticleMATERIALS SCIENCE

Grain boundary decohesion by nanoclustering Ni and Cr separately in CrMnFeCoNi high-entropy alloys

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Science Advances  06 Dec 2019:
Vol. 5, no. 12, eaay0639
DOI: 10.1126/sciadv.aay0639
  • Fig. 1 Temperature-dependent ductility.

    The uniform elongation-temperature relation of various fully recrystallized single-phase fcc HEAs/MEAs with different grain sizes (59).

  • Fig. 2 Mechanical properties of the single-phase coarse-grained Cr20Mn20Fe20Co20Ni20 HEA at different deformation temperatures.

    (A) Engineering stress-strain curves and (B) strain hardening rates at 25° to 800°C.

  • Fig. 3 Failure characteristics of the single-phase coarse-grained Cr20Mn20Fe20Co20Ni20 HEA.

    (A) Fracture surface and (C) lateral surface of the originally polished tensile sample after tensile tests at 25°C. (B) Fracture surface and (D) lateral surface of the tensile sample after tensile tests at 700°C. Inset of (D), the enlarged SEM image showing many cracks along the GBs.

  • Fig. 4 Nanosegregation at GBs.

    (A) TEM image of the single-phase coarse-grained Cr20Mn20Fe20Co20Ni20 sample after tensile test at 700°C. (B) Atom map of the tip showing GB segregation of impurities C and B. Cr (24 at %) and Ni (23 at %) isocomposition surfaces (C) viewed with the GB edge-on and (D) viewed from the GB normal. 1D compositional profiles (E) along the cyan arrow and (F) along the orange arrow indicated in (C); the shaded areas represent the approximate GB regions in thickness direction.

  • Fig. 5 Mechanical properties and failure characteristics of the dual-phase Cr26Mn20Fe20Co20Ni14 HEA.

    (A) Engineering stress-strain curves at 25° to 700°C. (B and C) Lateral fracture surfaces of the tensile samples after tensile tests at 500° and 700°C, respectively. (D and E) Fracture surfaces of the sample after tensile tests at 500° and 700°C, respectively.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/12/eaay0639/DC1

    Fig. S1. Mechanical properties of various single-phase fcc HEAs/MEAs on the elements Al, Cr, Mn, Fe, Co, and Ni.

    Fig. S2. Microstructure of the 1000°C annealed Cr20Mn20Fe20Co20Ni20 HEA.

    Fig. S3. Microstructure of the 1000°C annealed Cr20Mn20Fe20Co20Ni20 sample after tensile test at 700°C.

    Fig. S4. Segregation of trace elements C and B at the GB.

    Fig. S5. Microstructure of the dual-phase Cr26Mn20Fe20Co20Ni14 HEA.

    Table S1. Compositions of GB intermetallic phases.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Mechanical properties of various single-phase fcc HEAs/MEAs on the elements Al, Cr, Mn, Fe, Co, and Ni.
    • Fig. S2. Microstructure of the 1000°C annealed Cr20Mn20Fe20Co20Ni20 HEA.
    • Fig. S3. Microstructure of the 1000°C annealed Cr20Mn20Fe20Co20Ni20 sample after tensile test at 700°C.
    • Fig. S4. Segregation of trace elements C and B at the GB.
    • Fig. S5. Microstructure of the dual-phase Cr26Mn20Fe20Co20Ni14 HEA.
    • Table S1. Compositions of GB intermetallic phases.

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