Significant Contribution to Strength Enhancement from Deformation Twins in Thermomechanically Processed Al0.1CoCrFeNi Microstructures

  • Sindhura GangireddyEmail author
  • Daniel Whitaker
  • Rajiv S. Mishra


Strengthening mechanisms from thermomechanical processing treatments were explored in single-phase FCC high-entropy alloy Al0.1CoCrFeNi. Cold work offers substantial strengthening in this low stacking fault energy material owing to the resultant high work hardening rates. An enormous increase in yield strength of ~ 275% was obtained in 40% rolled material, but was accompanied by a steep drop in ductility. Recovery and recrystallization annealing treatments were investigated for improving elongation and obtaining better balance of strength–ductility combinations. Formation of novel microstructures from the different processing routes was examined. X-ray diffraction peak broadening and mechanical test results were coupled to estimate micro-strain in the different conditions and understand micro-strain’s correlation to strength. Retention of large-scale deformation twins formed during cold rolling is shown to play a key role in elevation of yield strength after heat treatments.


Al0.1CoCrFeNi dislocation hardening high-entropy alloy mechanical properties partial recrystallization recovery thermomechanical processing 



The work was performed under a cooperative agreement between the Army Research Laboratory and the University of North Texas (W911NF-16-2-0189). We also acknowledge the Materials Research Facility at UNT for microscopy facilities.

Data Availability

The raw data and the processing required to reproduce these findings are available to download and will be uploaded along with the manuscript.


  1. 1.
    M.C. Gao, High-Entropy Alloys, Springer, New York, 2016CrossRefGoogle Scholar
  2. 2.
    J.W. Yeh, Novel Alloy Concept, Challenges and Opportunities of High-Entropy Alloys, Frontiers Design Materials, B. Raj, Ed., CRC Press, Boca Raton, 2007, p 31–47Google Scholar
  3. 3.
    M.-H. Tsai, High-Entropy Alloys: A Critical Review, Mater. Res. Lett., 2014, 2(3), p 107–123CrossRefGoogle Scholar
  4. 4.
    Y. Zhang, Solid-Solution Phase Formation Rules for Multi-Component Alloys, Adv. Eng. Mater., 2008, 10(6), p 534–538CrossRefGoogle Scholar
  5. 5.
    W.R. Wang, Phases, Microstructure and Mechanical Properties of AlxCoCrFeNi High-Entropy Alloys at Elevated Temperatures, J. Alloys Compd., 2014, 589, p 143–152CrossRefGoogle Scholar
  6. 6.
    W.R. Wang, Effects of Al Addition on the Microstructure and Mechanical Property of AlxCoCrFeNi High-Entropy Alloys, Intermetallics, 2012, 26, p 44–51CrossRefGoogle Scholar
  7. 7.
    J. Joseph, Understanding the Mechanical Behaviour and the Large Strength/Ductility Differences Between FCC and BCC AlxCoCrFeNi High Entropy Alloys, J. Alloys Compd., 2017, 726, p 885–895CrossRefGoogle Scholar
  8. 8.
    H.P. Chou, Microstructure, Thermophysical and Electrical Properties in AlxCoCrFeNi (0 ≤ x ≤ 2) High-Entropy Alloys, Mater. Sci. Eng. B, 2009, 163(3), p 184–189CrossRefGoogle Scholar
  9. 9.
    M. Komarasamy, Effect of Microstructure on the Deformation Mechanism of Friction Stir-Processed Al0.1CoCrFeNi High Entropy Alloy, Mater. Res. Lett., 2015, 3(1), p 30–34CrossRefGoogle Scholar
  10. 10.
    N. Kumar, High Strain-Rate Compressive Deformation Behavior of the Al0.1CrFeCoNi High Entropy Alloy, Mater. Des., 2015, 86, p 598–602CrossRefGoogle Scholar
  11. 11.
    F. Otto, The Influences of Temperature and Microstructure on the Tensile Properties of a CoCrFeMnNi High-Entropy Alloy, Acta Mater., 2013, 61(15), p 5743–5755CrossRefGoogle Scholar
  12. 12.
    A. Gali, Tensile Properties of High- and Medium-Entropy Alloys, Intermetallics, 2013, 39, p 74–78CrossRefGoogle Scholar
  13. 13.
    S. Asgari, Strain Hardening Regimes and Microstructural Evolution During Large Strain Compression of Low Stacking Fault Energy FCC Alloys that Form Deformation Twins, Metall. Mater. Trans. A, 1997, 28(9), p 1781–1795CrossRefGoogle Scholar
  14. 14.
    Y.Z. Tian, Significant Contribution of Stacking Faults to the Strain Hardening Behavior of Cu-15% Al Alloy with Different Grain Sizes, Sci. Rep., 2015, 5, p 16707CrossRefGoogle Scholar
  15. 15.
    G.K. Williamson, X-Ray Line Broadening from Filed Aluminium and Wolfram, Acta Metall., 1953, 1(1), p 22–31CrossRefGoogle Scholar
  16. 16.
    G.K. Williamson, III. Dislocation Densities in Some Annealed and Cold-Worked Metals from Measurements on the X-Ray Debye-Scherrer Spectrum, Philos. Mag., 1956, 1(1), p 34–46CrossRefGoogle Scholar
  17. 17.
    M. Karolus, Crystallite Size and Lattice Strain in Nanocrystalline Ni-Mo Alloys Studied by Rietveld Refinement, J. Alloys Compd., 2004, 367(1-2), p 235–238CrossRefGoogle Scholar
  18. 18.
    S. Kumari, Strain Anisotropy in Freestanding Germanium Nanoparticles Synthesized by Ball Milling, J. Nanosci. Nanotechnol., 2009, 9(9), p 5231–5236CrossRefGoogle Scholar
  19. 19.
    M. Komarasamy, Serration Behavior and Negative Strain Rate Sensitivity of Al0.1CoCrFeNi High Entropy Alloy, Intermetallics, 2017, 84, p 20–24CrossRefGoogle Scholar
  20. 20.
    X. San, Effect of Stacking Fault Energy on Mechanical Properties of Ultrafine-Grain Cu and Cu-Al Alloy Processed by Cold-Rolling, Trans. Nonferr. Met. Soc. China, 2012, 22(4), p 819–824CrossRefGoogle Scholar
  21. 21.
    S.W. Wu, Strong Grain-Size Effect on Deformation Twinning of an Al0.1CoCrFeNi High-Entropy Alloy, Mater. Res. Lett., 2017, 5(4), p 276–283CrossRefGoogle Scholar
  22. 22.
    X.D. Xu, Transmission Electron Microscopy Characterization of Dislocation Structure in a Face-Centered Cubic High-Entropy Alloy Al0.1CoCrFeNi, Acta Mater., 2018, 144, p 107–115CrossRefGoogle Scholar
  23. 23.
    T.H. Courtney, Mechanical Behavior of Materials, Waveland Press, Long Grove, 2005Google Scholar

Copyright information

© ASM International 2019

Authors and Affiliations

  • Sindhura Gangireddy
    • 1
    Email author
  • Daniel Whitaker
    • 1
  • Rajiv S. Mishra
    • 1
  1. 1.AMMPIUniversity of North TexasDentonUSA

Personalised recommendations