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Title: Microband induced plasticity and the temperature dependence of the mechanical properties of a carbon-doped FeNiMnAlCr high entropy alloy

Here, the uniaxial mechanical properties of the high entropy alloy (HEA) Fe 40.4Ni 11.3Mn 34.8Al 7.5Cr 6 doped with 1.1 at.% C have been determined for both the as-cast and recrystallized states at temperatures from 77 to 973 K. Very high yield strengths were obtained at 77 K of 928 MPa for the as-cast HEA and 1037 MPa for the recrystallized HEA. The yield strength decreased sharply to 293 K and more slowly to 973 K, where it was ~200 MPa [11] in both conditions. The lattice friction stress, which results from the increase of the Peierls barrier, was the major contributor to the large yield strength at 77 K. On the other hand, the grain boundaries lose their strengthening ability at a high temperature, which largely accounts for the sharp drop in yield strength of the fine-grained (5 μm) recrystallized HEA at 973 K. The elongation to failure was highest at 293 K and 673 K with the lowest values at 77 K. Transmission electron microscopy was used to study the effects of temperature on the deformation mechanisms of the HEAs, especially the temperature dependence of the microband-induced plasticity effect. At temperatures ranging from 77 K to 673 Kmore » microbands form in the as-cast HEA, while dislocation clusters were observed in the recrystallized HEA over this temperature range. Only tangled dislocations were found at 973 K for both the as-cast and recrystallized HEA due to thermally-activated deformation.« less
Authors:
 [1] ; ORCiD logo [2] ;  [1]
  1. Dartmouth College, Hanover, NH (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 139; Journal Issue: C; Journal ID: ISSN 1044-5803
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; High entropy alloy; Mechanical properties; Dislocation structures; Microbands
OSTI Identifier:
1459317

Wang, Zhangwei, Bei, Hongbin, and Baker, Ian. Microband induced plasticity and the temperature dependence of the mechanical properties of a carbon-doped FeNiMnAlCr high entropy alloy. United States: N. p., Web. doi:10.1016/j.matchar.2018.03.017.
Wang, Zhangwei, Bei, Hongbin, & Baker, Ian. Microband induced plasticity and the temperature dependence of the mechanical properties of a carbon-doped FeNiMnAlCr high entropy alloy. United States. doi:10.1016/j.matchar.2018.03.017.
Wang, Zhangwei, Bei, Hongbin, and Baker, Ian. 2018. "Microband induced plasticity and the temperature dependence of the mechanical properties of a carbon-doped FeNiMnAlCr high entropy alloy". United States. doi:10.1016/j.matchar.2018.03.017.
@article{osti_1459317,
title = {Microband induced plasticity and the temperature dependence of the mechanical properties of a carbon-doped FeNiMnAlCr high entropy alloy},
author = {Wang, Zhangwei and Bei, Hongbin and Baker, Ian},
abstractNote = {Here, the uniaxial mechanical properties of the high entropy alloy (HEA) Fe40.4Ni11.3Mn34.8Al7.5Cr6 doped with 1.1 at.% C have been determined for both the as-cast and recrystallized states at temperatures from 77 to 973 K. Very high yield strengths were obtained at 77 K of 928 MPa for the as-cast HEA and 1037 MPa for the recrystallized HEA. The yield strength decreased sharply to 293 K and more slowly to 973 K, where it was ~200 MPa [11] in both conditions. The lattice friction stress, which results from the increase of the Peierls barrier, was the major contributor to the large yield strength at 77 K. On the other hand, the grain boundaries lose their strengthening ability at a high temperature, which largely accounts for the sharp drop in yield strength of the fine-grained (5 μm) recrystallized HEA at 973 K. The elongation to failure was highest at 293 K and 673 K with the lowest values at 77 K. Transmission electron microscopy was used to study the effects of temperature on the deformation mechanisms of the HEAs, especially the temperature dependence of the microband-induced plasticity effect. At temperatures ranging from 77 K to 673 K microbands form in the as-cast HEA, while dislocation clusters were observed in the recrystallized HEA over this temperature range. Only tangled dislocations were found at 973 K for both the as-cast and recrystallized HEA due to thermally-activated deformation.},
doi = {10.1016/j.matchar.2018.03.017},
journal = {Materials Characterization},
number = C,
volume = 139,
place = {United States},
year = {2018},
month = {3}
}