Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing

Abstract

Additive manufacturing produces net-shaped components layer by layer for engineering applications1,2,3,4,5,6,7. The additive manufacture of metal alloys by laser powder bed fusion (L-PBF) involves large temperature gradients and rapid cooling2,6, which enables microstructural refinement at the nanoscale to achieve high strength. However, high-strength nanostructured alloys produced by laser additive manufacturing often have limited ductility3. Here we use L-PBF to print dual-phase nanolamellar high-entropy alloys (HEAs) of AlCoCrFeNi2.1 that exhibit a combination of a high yield strength of about 1.3 gigapascals and a large uniform elongation of about 14 per cent, which surpasses those of other state-of-the-art additively manufactured metal alloys. The high yield strength stems from the strong strengthening effects of the dual-phase structures that consist of alternating face-centred cubic and body-centred cubic nanolamellae; the body-centred cubic nanolamellae exhibit higher strengths and higher hardening rates than the face-centred cubic nanolamellae. The large tensile ductility arises owing to the high work-hardening capability of the as-printed hierarchical microstructures in the form of dual-phase nanolamellae embedded in microscale eutectic colonies, which have nearly random orientations to promote isotropic mechanical properties. The mechanistic insights into the deformation behaviour of additively manufactured HEAs have broad implications for the development of hierarchical, dual- and multi-phase, nanostructured alloys with exceptional mechanical properties.

Your institute does not have access to this article

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Fig. 1: Microstructure of AM AlCoCrFeNi2.1 EHEA.
Fig. 2: Tensile properties of AM AlCoCrFeNi2.1 EHEAs.
Fig. 3: Lattice strains and stress partitioning in fcc and bcc phases during uniaxial tension.
Fig. 4: Meso- and atomic-scale deformation structures.

Data availability

The data of this study are included in the article, the Extended Data and the Supplementary Information.

Code availability

The code used for finite-element analyses is publicly available on the GitHub repository at https://github.com/yzhang951/CPFEM-VUMAT/tree/main/AM-HEA.

References

  1. DebRoy, T., Mukherjee, T., Wei, H. L., Elmer, J. W. & Milewski, J. O. Metallurgy, mechanistic models and machine learning in metal printing. Nat. Rev. Mater. 6, 48–68 (2021).

    ADS  CAS  Article  Google Scholar 

  2. Martin, J. H. et al. 3D printing of high-strength aluminium alloys. Nature 549, 365–369 (2017).

    ADS  CAS  PubMed  Article  Google Scholar 

  3. Zhang, D. et al. Additive manufacturing of ultrafine-grained high-strength titanium alloys. Nature 576, 91–95 (2019).

    ADS  CAS  PubMed  Article  Google Scholar 

  4. Pham, M.-S., Liu, C., Todd, I. & Lertthanasarn, J. Damage-tolerant architected materials inspired by crystal microstructure. Nature 565, 305–311 (2019).

    ADS  CAS  PubMed  Article  Google Scholar 

  5. Kürnsteiner, P. et al. High-strength Damascus steel by additive manufacturing. Nature 582, 515–519 (2020).

    ADS  PubMed  Article  CAS  Google Scholar 

  6. Wang, Y. M. et al. Additively manufactured hierarchical stainless steels with high strength and ductility. Nat. Mater. 17, 63–71 (2018).

    ADS  CAS  PubMed  Article  Google Scholar 

  7. Cunningham, R. et al. Keyhole threshold and morphology in laser melting revealed by ultrahigh-speed X-ray imaging. Science 363, 849–852 (2019).

    ADS  CAS  PubMed  Article  Google Scholar 

  8. Todaro, C. J. et al. Grain structure control during metal 3D printing by high-intensity ultrasound. Nat. Commun. 11, 142 (2020).

    ADS  CAS  PubMed  PubMed Central  Article  Google Scholar 

  9. Murray, S. P. et al. A defect-resistant Co–Ni superalloy for 3D printing. Nat. Commun. 11, 4975 (2020).

    ADS  CAS  PubMed  PubMed Central  Article  Google Scholar 

  10. Barriobero-Vila, P. et al. Peritectic titanium alloys for 3D printing. Nat. Commun. 9, 3426 (2018).

    ADS  PubMed  PubMed Central  Article  CAS  Google Scholar 

  11. Brif, Y., Thomas, M. & Todd, I. The use of high-entropy alloys in additive manufacturing. Scr. Mater. 99, 93–96 (2015).

    CAS  Article  Google Scholar 

  12. Jensen, J. K. et al. Characterization of the microstructure of the compositionally complex alloy Al1Mo0.5Nb1Ta0.5Ti1Zr1. Scr. Mater. 121, 1–4 (2016).

    CAS  Article  Google Scholar 

  13. George, E. P., Raabe, D. & Ritchie, R. O. High-entropy alloys. Nat. Rev. Mater. 4, 515–534 (2019).

    ADS  CAS  Article  Google Scholar 

  14. Lu, Y. et al. A promising new class of high-temperature alloys: eutectic high-entropy alloys. Sci. Rep. 4, 6200 (2014).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  15. Zhu, Y. et al. Enabling stronger eutectic high-entropy alloys with larger ductility by 3D printed directional lamellae. Addit. Manuf. 39, 101901 (2021).

    CAS  Google Scholar 

  16. Shi, P. et al. Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys. Science 373, 912–918 (2021).

    ADS  CAS  PubMed  Article  Google Scholar 

  17. Zhu, Y. T. & Liao, X. Retaining ductility. Nat. Mater. 3, 351–352 (2004).

    ADS  CAS  PubMed  Article  Google Scholar 

  18. Zheng, S. et al. High-strength and thermally stable bulk nanolayered composites due to twin-induced interfaces. Nat. Commun. 4, 1696 (2013).

    ADS  PubMed  Article  CAS  Google Scholar 

  19. Cheng, Z., Zhou, H., Lu, Q., Gao, H. & Lu, L. Extra strengthening and work hardening in gradient nanotwinned metals. Science 362, eaau1925 (2018).

    ADS  PubMed  Article  CAS  Google Scholar 

  20. Fan, L. et al. Ultrahigh strength and ductility in newly developed materials with coherent nanolamellar architectures. Nat. Commun. 11, 6240 (2020).

    ADS  CAS  PubMed  PubMed Central  Article  Google Scholar 

  21. Thomas, M., Baxter, G. J. & Todd, I. Normalised model-based processing diagrams for additive layer manufacture of engineering alloys. Acta Mater. 108, 26–35 (2016).

    ADS  CAS  Article  Google Scholar 

  22. Pham, M.-S., Dovgyy, B., Hooper, P. A., Gourlay, C. M. & Piglione, A. The role of side-branching in microstructure development in laser powder-bed fusion. Nat. Commun. 11, 749 (2020).

    ADS  CAS  PubMed  PubMed Central  Article  Google Scholar 

  23. Bhattacharjee, T. et al. Simultaneous strength–ductility enhancement of a nano-lamellar AlCoCrFeNi2.1 eutectic high entropy alloy by cryo-rolling and annealing. Sci. Rep. 8, 3276 (2018).

    ADS  CAS  PubMed  PubMed Central  Article  Google Scholar 

  24. Shi, P. et al. Enhanced strength–ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae. Nat. Commun. 10, 489 (2019).

    ADS  CAS  PubMed  PubMed Central  Article  Google Scholar 

  25. Gao, X. et al. Microstructural origins of high strength and high ductility in an AlCoCrFeNi2.1 eutectic high-entropy alloy. Acta Mater. 141, 59–66 (2017).

    ADS  CAS  Article  Google Scholar 

  26. Misra, A., Hirth, J. P. & Hoagland, R. G. Length-scale-dependent deformation mechanisms in incoherent metallic multilayered composites. Acta Mater. 53, 4817–4824 (2005).

    ADS  CAS  Article  Google Scholar 

  27. Porter, D. A. & Easterling, K. E. Phase Transformations in Metals and Alloys (CRC, 1981).

  28. An, Z. et al. Spinodal-modulated solid solution delivers a strong and ductile refractory high-entropy alloy. Mater. Horiz. 8, 948–955 (2021).

    CAS  PubMed  Article  Google Scholar 

  29. Chen, W. et al. Microscale residual stresses in additively manufactured stainless steel. Nat. Commun. 10, 4338 (2019).

    ADS  PubMed  PubMed Central  Article  CAS  Google Scholar 

  30. Naeem, M. et al. Cooperative deformation in high-entropy alloys at ultralow temperatures. Sci. Adv. 6, eaax4002 (2020).

    ADS  PubMed  PubMed Central  Article  CAS  Google Scholar 

  31. Raabe, D. et al. Metallic composites processed via extreme deformation: toward the limits of strength in bulk materials. MRS Bull. 35, 982–991 (2010).

    CAS  Article  Google Scholar 

  32. Wang, Y., Ohnuki, T., Tomota, Y., Harjo, S. & Ohmura, T. Multi-scaled heterogeneous deformation behavior of pearlite steel studied by in situ neutron diffraction. Scr. Mater. 140, 45–49 (2017).

    Article  CAS  Google Scholar 

  33. Ghosh, P., Kormout, K. S., Lienert, U., Keckes, J. & Pippan, R. Deformation characteristics of ultrafine grained and nanocrystalline iron and pearlitic steel—an in situ synchrotron investigation. Acta Mater. 160, 22–33 (2018).

    ADS  CAS  Article  Google Scholar 

  34. Bhadeshia, H. Cementite. Int. Mater. Rev. 65, 1–27 (2020).

    CAS  Article  Google Scholar 

  35. Jia, D., Ramesh, K. T. & Ma, E. Effects of nanocrystalline and ultrafine grain sizes on constitutive behavior and shear bands in iron. Acta Mater. 51, 3495–3509 (2003).

    ADS  CAS  Article  Google Scholar 

  36. Wei, Q., Jiao, T., Ramesh, K. T. & Ma, E. Nano-structured vanadium: processing and mechanical properties under quasi-static and dynamic compression. Scr. Mater. 50, 359–364 (2004).

    CAS  Article  Google Scholar 

  37. Hull, D. & Bacon, D. J. Introduction to Dislocations (Butterworth-Heinemann, 2001).

  38. Wang, F. et al. Multiplicity of dislocation pathways in a refractory multiprincipal element alloy. Science 370, 95–101 (2020).

    ADS  CAS  PubMed  Article  Google Scholar 

  39. Lee, C. et al. Temperature dependence of elastic and plastic deformation behavior of a refractory high-entropy alloy. Sci. Adv. 6, eaaz4748 (2020).

    ADS  CAS  PubMed  Article  Google Scholar 

  40. Chen, M. et al. Deformation twinning in nanocrystalline aluminum. Science 300, 1275–1277 (2003).

    ADS  CAS  PubMed  Article  Google Scholar 

  41. Rao, S. I. et al. Atomistic simulations of dislocations in a model bcc multicomponent concentrated solid solution alloy. Acta Mater. 125, 311–320 (2017).

    ADS  CAS  Article  Google Scholar 

  42. Lei, Z. et al. Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes. Nature 563, 546–550 (2018).

    ADS  CAS  PubMed  Article  Google Scholar 

  43. Ding, Q. et al. Tuning element distribution, structure and properties by composition in high-entropy alloys. Nature 574, 223–227 (2019).

    ADS  CAS  PubMed  Article  Google Scholar 

  44. George, E. P., Curtin, W. A. & Tasan, C. C. High entropy alloys: a focused review of mechanical properties and deformation mechanisms. Acta Mater. 188, 435–474 (2020).

    ADS  CAS  Article  Google Scholar 

  45. Zhu, Y. et al. Heterostructured materials: superior properties from hetero-zone interaction. Mater. Res. Lett. 9, 1–31 (2021).

    Article  CAS  Google Scholar 

  46. Cheng, Z. et al. Unraveling the origin of extra strengthening in gradient nanotwinned metals. Proc. Natl Acad. Sci. USA 119, e2116808119 (2022).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  47. Dickson, J., Boutin, J. & Handfield, L. A comparison of two simple methods for measuring cyclic internal and effective stresses. Mater. Sci. Eng. 64, L7–L11 (1984).

    CAS  Article  Google Scholar 

  48. Wu, Q. et al. Uncovering the eutectics design by machine learning in the Al–Co–Cr–Fe–Ni high entropy system. Acta Mater. 182, 278–286 (2020).

    ADS  CAS  Article  Google Scholar 

  49. Zimmermann, M., Carrard, M. & Kurz, W. Rapid solidification of Al–Cu eutectic alloy by laser remelting. Acta Metall. 37, 3305–3313 (1989).

    CAS  Article  Google Scholar 

  50. Sharma, G., Ramanujan, R. V. & Tiwari, G. P. Instability mechanisms in lamellar microstructures. Acta Mater. 48, 875–889 (2000).

    ADS  CAS  Article  Google Scholar 

  51. An, K. et al. First in situ lattice strains measurements under load at VULCAN. Metall. Mater. Trans. A 42, 95–99 (2011).

    CAS  Article  Google Scholar 

  52. An, K., Chen, Y. & Stoica, A. D. VULCAN: a “hammer” for high-temperature materials research. MRS Bull. 44, 878–885 (2019).

    ADS  Article  Google Scholar 

  53. An, K. VDRIVE: Data Reduction and Interactive Visualization Software for Event Mode Neutron Diffraction ORNL Report No. ORNL-TM-2012-621 (Oak Ridge National Laboratory, 2012).

  54. Larson, A. C. & Von Dreele, R. B. General Structure Analysis System (GSAS) Report LAUR 86-748 (Los Alamos National Laboratory, 2004).

  55. Courtney, T. H. Mechanical Behavior of Materials (Waveland, 2005).

  56. He, J. Y. et al. A precipitation-hardened high-entropy alloy with outstanding tensile properties. Acta Mater. 102, 187–196 (2016).

    ADS  CAS  Article  Google Scholar 

  57. Zhang, X., Hansen, N., Godfrey, A. & Huang, X. Dislocation-based plasticity and strengthening mechanisms in sub-20 nm lamellar structures in pearlitic steel wire. Acta Mater. 114, 176–183 (2016).

    ADS  CAS  Article  Google Scholar 

Download references

Acknowledgements

We thank D. Follette, P. Hou, M. Wu, K. A. Beyer and M. J. Frost for their experimental assistance. W.C. acknowledges support from the US National Science Foundation (DMR-2004429) and UMass Amherst Faculty Startup Fund. T.Z. acknowledges support from the US National Science Foundation (DMR-1810720 and DMR-2004412). Y.M.W. acknowledges support from the US National Science Foundation (DMR-2104933). T.V. acknowledges support from the Laboratory Directed Research and Development (LDRD) programme (21-LW-027) at Lawrence Livermore National Laboratory (LLNL). His work was performed under the auspices of the US Department of Energy (DOE) by LLNL under contract no. DE-AC52-07NA27344. In situ neutron-diffraction work was carried out at the Spallation Neutron Source (SNS), which is a US DOE user facility at the Oak Ridge National Laboratory (ORNL), sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences. APT research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US DOE Office of Science User Facility at ORNL. We thank J. Burns for assistance in performing the APT sample preparation and running the APT experiments. This research also used high-energy X-ray resources of the Advanced Photon Source (Beamline 11-ID-C), a US DOE Office of Science User Facility operated at Argonne National Laboratory under contract number DE-AC02-06CH11357.

Author information

Authors and Affiliations

Authors

Contributions

J.R. and W.C. developed the three-dimensional printing-process map. J.R. and F.K. fabricated all samples and performed the processing parameters optimization. J.R., Y.L., L.L. and S.P. performed the optical microscopy and SEM microstructure characterization and mechanical testing. D.Z., K.Y.X., G.G., T.V. and Y.M.W. performed the EBSD and TEM characterization and analyses. J.R., Y.C., K.A. and W.C. conducted in situ neutron-diffraction experiments and analysed the data. J.D.P. collected and analysed the APT data. S.G. conducted the thermodynamic calculation. Y.Z. and T.Z. developed the DP-CPFE model and performed numerical simulations. J.R., Y.Z., D.Z., K.Y.X. T.Z. and W.C. drafted the initial manuscript. W.C. conceived, designed and led the project. All co-authors contributed to the data analysis and discussion.

Corresponding authors

Correspondence to Ting Zhu or Wen Chen.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature thanks Sheng Guo, Minh-Son Pham and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Pole figures of as-printed AlCoCrFeNi2.1 acquired by neutron diffraction.

a, Pole figures of FCC- (111), (200), (220), and (311) before loading. b, Pole figures of BCC-(110), (200), (211), and (321) before loading. c, Pole figures of FCC- (111), (200), (220), and (311) after fracture. Because the BCC peaks display extensive broadening after fracture, single-peak fittings are not convergent at lots of beam incident directions and pole figures of BCC orientations after fracture are not available. In all pole figures, the loading direction (LD) is out of plane, the transverse direction (TD) is along the horizontal direction, and the build direction (BD) is along the vertical direction. Before loading, the as-printed sample shows a rather weak texture with slightly preferred orientation of FCC-(110)//BD. After fracture, the FCC-(111)//LD texture is developed, suggesting prominent dislocation slips on {111} planes in the FCC phase.

Extended Data Fig. 2 High-resolution TEM image showing the consistent crystal structure within BCC nanolamellae.

The inset shows the corresponding Fast Fourier Transform (FFT) diffractogram of the entire area that can provide chemical ordering information. No alternating intensity variation is observed in the FFT diffractogram, suggesting that no apparent ordered B2 phase is present.

Extended Data Fig. 3 Extreme processing conditions enabled by L-PBF and the resulting highly metastable microstructure of multi-component eutectic alloys.

a, Comparison of cooling rate and thermal gradient between several additive manufacturing methods such as laser powder bed fusion (L-PBF) – used in this work, laser directed energy deposition (L-DED), wire arc additive manufacturing (WAAM), as well as conventional casting (CC) and directional solidification (DS)1. Extremely large cooling rates and thermal gradients are inherent to the unique spatial-temporal feature of L-PBF and thus give rise to the diffusion-limited solidification and far-from-equilibrium microstructure of our EHEAs. b, Schematic illustration of the cooling rate effects on microstructural morphologies and length scales for typical dual-phase multi-component eutectic alloys.

Extended Data Fig. 4 Kocks-Mecking plot showing the strain-hardening rate of as-printed AlCoCrFeNi2.1.

Strain-hardening rate (i.e., rate of increase of true stress with respect to true strain) is plotted as a function of true stress. Symbols represent experimental data points and the solid line is the fitting curve.

Extended Data Fig. 5 Tensile stress–strain curves of as-printed AlCoCrFeNi2.1 EHEAs along different directions.

Comparable mechanical properties of these samples at a similar build height demonstrate the isotropic mechanical behaviour of AM AlCoCrFeNi2.1 EHEA consisting of nanolamellar eutectic colonies with nearly random orientations.

Extended Data Fig. 6 TEM images showing stacking faults (SFs) in strained FCC nanolamellae.

a, SFs observed at the strain level of 5%. b, Same as a except at 15%. SFs are highlighted by yellow arrows.

Extended Data Fig. 7 Evolution of back stress during tensile deformation of as-printed AlCoCrFeNi2.1.

a, Loading–unloading-reloading (LUR) true stress–strain curve. b, A representative LUR cycle showing the hysteresis loop. The back stress is calculated by Dickson’s method and thus defined as σb = σ0σe = (σ0 + σu)/2 – σ*/2, where σb denotes the back stress, σ0 the flow stress before unloading, σe the effective stress, σu the unloading yield stress, and σ* the viscous stress. c, Flow stress, back stress, and effective stress versus true strain during tensile deformation. Error bars represent the standard deviation.

Extended Data Fig. 8 AM Ni40Co20Fe10Cr10Al18W2 EHEA with high strength and large tensile ductility.

a, 3D-reconstructed optical micrographs. b, Secondary electron micrograph showing the microscale eutectic colonies with different growth directions. c, Secondary electron micrograph revealing the typical nanolamellar structure. d, 3D-reconstructed EBSD IPF maps. The eutectic colony size distribution is obtained from the top-view map. The 001, 110, 111 pole figures of FCC phase are collected from the top-view EBSD map. Note that the BCC nanolamellae are difficult to index by EBSD due to their ultra-small thicknesses of ~35 nm. e, Lamellar thickness distribution of BCC and FCC lamellae in as-printed Ni40Co20Fe10Cr10Al18W2 EHEA. The average interlamellar spacing (λ ≈ 133 nm) is ~5 times smaller than that in the as-cast Ni40Co20Fe10Cr10Al18W2 (λ ≈ 0.82 μm). f, Neutron-diffraction pattern of AM Ni40Co20Fe10Cr10Al18W2 composed of FCC and BCC/B2 phases. g, Quasi-static tensile stress–strain curves of the as-cast and AM Ni40Co20Fe10Cr10Al18W2 EHEAs. Our AM EHEA exhibits a high yield strength of ~1.5 GPa and ultimate tensile strength of ~1.7 GPa, which outperform the as-cast counterpart by twofold with no significant loss in ductility. Note that the tensile stress–strain curve of the as-cast sample (dashed line) is taken from the literature; the substantially low elastic modulus and large elastic strain limit are likely due to the inaccurate strain measurement of this literature result.

Extended Data Table 1 Compositions of FCC and BCC phases in as-printed AlCoCrFeNi2.1, compared with as-cast counterpart25

Supplementary information

Supplementary Information

This file contains Supplementary text, tables, figures, legends for videos and references.

Supplementary Video 1

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ren, J., Zhang, Y., Zhao, D. et al. Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing. Nature 608, 62–68 (2022). https://doi.org/10.1038/s41586-022-04914-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-022-04914-8

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing