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Title: Secondary phases in Al xCoCrFeNi high-entropy alloys: An in-situ TEM heating study and thermodynamic appraisal

Abstract

Secondary phases, either introduced by alloying or heat treatment, are commonly present in most high-entropy alloys (HEAs). Understanding the formation of secondary phases at high temperatures, and their effect on mechanical properties, is a critical issue that is undertaken in the present paper, using the Al xCoCrFeNi (x = 0.3, 0.5, and 0.7) as a model alloy. The in-situ transmission-electron-microscopy (TEM) heating observation, an atom-probe-tomography (APT) study for the reference starting materials (Al 0.3 and Al 0.5 alloys), and thermodynamic calculations for all three alloys, are performed to investigate (1) the aluminum effect on the secondary-phase fractions, (2) the annealing-twinning formation in the face-centered-cubic (FCC) matrix, (3) the strengthening effect of the secondary ordered body-centered-cubic (B2) phase, and (4) the nucleation path of the σ secondary phase thoroughly. Finally, the present work will substantially optimize the alloy design of HEAs and facilitate applications of HEAs to a wide temperature range.

Authors:
 [1];  [2];  [3];  [3];  [4];  [2];  [2];  [5];  [5];  [6];  [2];  [3]
  1. Harbin Inst. of Technology (China). School of Materials Science and Engineering. Inst. for Advanced Ceramics; Univ. of Groningen (Netherlands). Zernike Inst. for Advanced Materials. Dept. of Applied Physics; Univ. of Maryland, College Park, MD (United States). Maryland NanoCenter
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
  3. Univ. of Groningen (Netherlands). Zernike Inst. for Advanced Materials. Dept. of Applied Physics
  4. CompuTherm, LLC, Middleton, WI (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences
  6. Harbin Inst. of Technology (China). School of Materials Science and Engineering. Inst. for Advanced Ceramics
Publication Date:
Research Org.:
Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Groningen (Netherlands); Harbin Inst. of Technology (China)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); US Army Research Office (ARO); Royal Netherlands Academy of Science (Netherlands); National Natural Science Foundation of China (NNSFC)
Contributing Org.:
Univ. of Maryland, College Park, MD (United States); CompuTherm, LLC, Middleton, WI (United States)
OSTI Identifier:
1352800
Alternate Identifier(s):
OSTI ID: 1398724
Grant/Contract Number:
FE0024054; FE0008855; FE0011194; AC05-00OR22725; DMR-1611180; W911NF-13-1-0438; 11CDP003; 51572054; 51021002; 51321061; FE-0008855; FE-0024054
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 131; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; High-entropy alloy; Secondary phases; In-situ heating TEM; Atom-probe-tomography; Thermodynamic calculations

Citation Formats

Rao, J. C., Diao, H. Y., Ocelík, V., Vainchtein, D., Zhang, C., Kuo, C., Tang, Z., Guo, W., Poplawsky, J. D., Zhou, Y., Liaw, P. K., and De Hosson, J. Th. M. Secondary phases in AlxCoCrFeNi high-entropy alloys: An in-situ TEM heating study and thermodynamic appraisal. United States: N. p., 2017. Web. doi:10.1016/j.actamat.2017.03.066.
Rao, J. C., Diao, H. Y., Ocelík, V., Vainchtein, D., Zhang, C., Kuo, C., Tang, Z., Guo, W., Poplawsky, J. D., Zhou, Y., Liaw, P. K., & De Hosson, J. Th. M. Secondary phases in AlxCoCrFeNi high-entropy alloys: An in-situ TEM heating study and thermodynamic appraisal. United States. doi:10.1016/j.actamat.2017.03.066.
Rao, J. C., Diao, H. Y., Ocelík, V., Vainchtein, D., Zhang, C., Kuo, C., Tang, Z., Guo, W., Poplawsky, J. D., Zhou, Y., Liaw, P. K., and De Hosson, J. Th. M. Mon . "Secondary phases in AlxCoCrFeNi high-entropy alloys: An in-situ TEM heating study and thermodynamic appraisal". United States. doi:10.1016/j.actamat.2017.03.066. https://www.osti.gov/servlets/purl/1352800.
@article{osti_1352800,
title = {Secondary phases in AlxCoCrFeNi high-entropy alloys: An in-situ TEM heating study and thermodynamic appraisal},
author = {Rao, J. C. and Diao, H. Y. and Ocelík, V. and Vainchtein, D. and Zhang, C. and Kuo, C. and Tang, Z. and Guo, W. and Poplawsky, J. D. and Zhou, Y. and Liaw, P. K. and De Hosson, J. Th. M.},
abstractNote = {Secondary phases, either introduced by alloying or heat treatment, are commonly present in most high-entropy alloys (HEAs). Understanding the formation of secondary phases at high temperatures, and their effect on mechanical properties, is a critical issue that is undertaken in the present paper, using the AlxCoCrFeNi (x = 0.3, 0.5, and 0.7) as a model alloy. The in-situ transmission-electron-microscopy (TEM) heating observation, an atom-probe-tomography (APT) study for the reference starting materials (Al0.3 and Al0.5 alloys), and thermodynamic calculations for all three alloys, are performed to investigate (1) the aluminum effect on the secondary-phase fractions, (2) the annealing-twinning formation in the face-centered-cubic (FCC) matrix, (3) the strengthening effect of the secondary ordered body-centered-cubic (B2) phase, and (4) the nucleation path of the σ secondary phase thoroughly. Finally, the present work will substantially optimize the alloy design of HEAs and facilitate applications of HEAs to a wide temperature range.},
doi = {10.1016/j.actamat.2017.03.066},
journal = {Acta Materialia},
number = ,
volume = 131,
place = {United States},
year = {Mon Mar 27 00:00:00 EDT 2017},
month = {Mon Mar 27 00:00:00 EDT 2017}
}

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