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Defect reconfiguration in a Ti–Al alloy via electroplasticity

Nature Materials volume 20, pages 468–472 (2021)Cite this article

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Abstract

It has been known for decades that the application of pulsed direct current can significantly enhance the formability of metals. However, the detailed mechanisms of this effect have been difficult to separate from simple Joule heating. Here, we study the electroplastic deformation of Ti–Al (7 at.% Al), an alloy that is uniquely suited for uncoupling this behaviour because, contrary to most metals, it has inherently lower ductility at higher temperature. We find that during mechanical deformation, electropulsing enhances cross-slip, producing a wavy dislocation morphology, and enhances twinning, which is similar to what occurs during cryogenic deformation. As a consequence, dislocations are prevented from localizing into planar slip bands that would lead to the early failure of the alloy under tension. Our results demonstrate that this macroscopic electroplastic behaviour originates from defect-level microstructural reconfiguration that cannot be rationalized by simple Joule heating.

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Fig. 1: Mechanical and thermal measurements of the material at different conditions.
Fig. 2: Comparison of dislocation morphology of samples pre-deformed to 5% of engineering strain.
Fig. 3: Cryogenic deformation shows similar behaviour as pulsing deformation at ambient temperature.
Fig. 4: Characterization of the deformation twinning in the electrical-biasing deformed sample.

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Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

References

  1. Conrad, H. Electroplasticity in metals and ceramics. Mater. Sci. Eng. A 287, 276–287 (2000).

    Article  Google Scholar 

  2. Troitskii, O. A. Electromechanical effect in metals. JETP Lett. 10, 11 (1969).

    Google Scholar 

  3. Troitskii, O. A. Effect of the electron state of a metal on its mechanical properties and the phenomenon of electroplasticity. Strength Mater. 9, 35–45 (1977).

    Article  Google Scholar 

  4. Okazaki, K., Kagawa, M. & Conrad, H. An evaluation of the contributions of skin, pinch and heating effects to the electroplastic effect in titatnium. Mater. Sci. Eng. 45, 109–116 (1980).

    Article  CAS  Google Scholar 

  5. Conrad, H., Sprecher, A. F., Cao, W. D. & Lu, X. P. Electroplasticity—the effect of electricity on the mechanical properties of metals. JOM 42, 28–33 (1990).

    Article  CAS  Google Scholar 

  6. Andre, D. et al. Investigation of the electroplastic effect using nanoindentation. Mater. Des. 183, 108153 (2019).

    Article  CAS  Google Scholar 

  7. Xiang, S. & Zhang, X. Dislocation structure evolution under electroplastic effect. Mater. Sci. Eng. A 761, 138026 (2019).

    Article  CAS  Google Scholar 

  8. Waryoba, D., Islam, Z., Wang, B. & Haque, A. Low temperature annealing of metals with electrical wind force effects. J. Mater. Sci. Technol. 35, 465–472 (2019).

    Article  Google Scholar 

  9. Sheng, Y. et al. Application of high-density electropulsing to improve the performance of metallic materials: mechanisms, microstructure and properties. Materials 11, 185 (2018).

    Article  Google Scholar 

  10. Li, W. et al. Non-octahedral-like dislocation glides in aluminum induced by athermal effect of electric pulse. J. Mater. Res. 31, 1193–1200 (2016).

    Article  CAS  Google Scholar 

  11. Wang, X. et al. Current-induced ductility enhancement of a magnesium alloy AZ31 in uniaxial micro-tension below 373 K. Materials 12, 111 (2019).

    Article  CAS  Google Scholar 

  12. Islam, Z., Wang, B. & Haque, A. Current density effects on the microstructure of zirconium thin films. Scr. Mater. 144, 18–21 (2018).

    Article  CAS  Google Scholar 

  13. Zhao, Y. et al. Electropulsing strengthened 2GPa boron steel with good ductility. Mater. Des. 43, 195–199 (2013).

    Article  CAS  Google Scholar 

  14. Sprecher, A. F., Mannan, S. L. & Conrad, H. Overview no. 49. Acta Metall. 34, 1145–1162 (1986).

    Article  CAS  Google Scholar 

  15. Noell, P. J., Rodelas, J. M., Ghanbari, Z. N. & Laursen, C. M. Microstructural modification of additively manufactured metals by electropulsing. Addit. Manuf. 33, 101128 (2020).

    CAS  Google Scholar 

  16. Qin, R. S. & Bhowmik, A. Computational thermodynamics in electric current metallurgy. Mater. Sci. Technol. 31, 1560–1563 (2015).

    Article  CAS  Google Scholar 

  17. Jiang, Y., Tang, G., Shek, C., Zhu, Y. & Xu, Z. On the thermodynamics and kinetics of electropulsing induced dissolution of β-Mg17Al12 phase in an aged Mg-9Al-1Zn. Acta Mater. 57, 4797–4808 (2009).

    Article  CAS  Google Scholar 

  18. Savenko, V. V. Electroplastic deformation by twinning metals. Acta Mech. Autom. 12, 259–264 (2018).

    Google Scholar 

  19. Kravchenko, V. Y. Effect of directed electron beam on moving dislocations. Sov. Phys. JETP 24, 1135–1142 (1967).

    Google Scholar 

  20. Roshchupkin, A. M. & Bataronov, I. V. Physical basis of the electroplastic deformation of metals. Russ. Phys. J. 39, 230–236 (1996).

    Article  Google Scholar 

  21. Klimov, K., Shnyrev, G. & Novikov, I. Electroplasticity in metals. J. Sov. Phys. Dokl. 19, 787–788 (1975).

    Google Scholar 

  22. Roshchupkin, A. M., Miloshenko, V. E. & Kalinin, V. E. The electron retardation of dislocations in metals. Fiz. Tverd. Tela 21, 909–910 (1979).

    CAS  Google Scholar 

  23. Molotskii, M. & Fleurov, V. Work hardening of crystals in a magnetic field. Philos. Mag. Lett. 73, 11–15 (1996).

    Article  CAS  Google Scholar 

  24. Molotskii, M. I. Theoretical basis for electro- and magnetoplasticity. Mater. Sci. Eng. A 287, 248–258 (2000).

    Article  Google Scholar 

  25. Lütjering, G. G. & Williams, J. C. Titanium (Springer, 2010).

  26. Zhang, R. et al. Direct imaging of short-range order and its impact on deformation in Ti-6Al. Sci. Adv. 5, eaax2799 (2019).

    Article  CAS  Google Scholar 

  27. Williams, J. C., Baggerly, R. G. & Paton, N. E. Deformation behavior of HCP Ti-Al alloy single crystals. Metall. Mater. Trans. A 33, 837–850 (2002).

  28. Venkataraman, A. et al. Study of structure and deformation pathways in Ti-7Al using atomistic simulations, experiments, and characterization. Metall. Mater. Trans. A 48, 2222–2236 (2017).

    Article  CAS  Google Scholar 

  29. Fitzner, A. et al. The effect of aluminium on twinning in binary alpha-titanium. Acta Mater. 103, 341–351 (2016).

    Article  CAS  Google Scholar 

  30. Conrad, H. On the strengthening of titanium by aluminum. Scr. Metall. 7, 509–512 (1973).

    Article  CAS  Google Scholar 

  31. Neeraj, T., Holc, D. H., Daehn, G. S. & Mills, M. J. Phenomenological and microstructural analysis of room temperature creep in titanium alloys. Acta Mater. 48, 1225–1238 (2000).

    Article  CAS  Google Scholar 

  32. Neeraj, T. & Mills, M. J. Observation and analysis of weak-fringing faults in Ti-6 wt% Al. Philos. Mag. A 82, 779–802 (2002).

    Article  CAS  Google Scholar 

  33. van de Walle, A. & Asta, M. First-principles investigation of perfect and diffuse antiphase boundaries in HCP-based Ti-Al alloys. Metall. Mater. Trans. A 33, 735–741 (2002).

    Article  Google Scholar 

  34. Lubarda, V. A., Meyers, M. A. & Vo, O. The onset of twinning in metals: a constitutive description. Acta Mater. 49, 4025–4039 (2001).

    Article  Google Scholar 

  35. Moskalenko, V. A., Startsev, V. I. & Kovaleva, V. N. Low temperature peculiarities of plastic deformation in titanium and its alloys. Cryogenics 20, 503–508 (1980).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We gratefully acknowledge funding from the US Office of Naval Research under grant no. N00014-17-1-2283. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-AC02-05CH11231.

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Author notes

  1. These authors contributed equally: Shiteng Zhao, Ruopeng Zhang.

Authors and Affiliations

  1. Department of Materials Science and Engineering, University of California, Berkeley, CA, USA

    Shiteng Zhao, Ruopeng Zhang, Yan Chong, Xiaoqing Li, Anas Abu-Odeh, Eric Rothchild, Daryl C. Chrzan, Mark Asta, J. W. Morris Jr. & Andrew M. Minor

  2. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    Shiteng Zhao, Ruopeng Zhang, Yan Chong, Xiaoqing Li & Andrew M. Minor

  3. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

    Daryl C. Chrzan & Mark Asta

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  1. Shiteng Zhao
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Contributions

S.Z. and A.M.M. proposed the experiments. S.Z., R.Z. and Y.C. performed the mechanical testing with electrical pulsing. S.Z. and R.Z. conducted the TEM and high-resolution STEM characterization of the resultant dislocation structures and twins. S.Z. conducted the EBSD. E.R. and D.C.C. estimated the magnetostriction and thermal diffusivity effects. R.Z., A.A. and X.L. assisted with the literature review. A.A. and M.A. provided the electrical free energy discussion. S.Z., J.W.M. and A.M.M. drafted the manuscript and all the authors contributed to the discussions. J.W.M. and A.M.M. supervised the project.

Corresponding author

Correspondence to Andrew M. Minor.

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Extended data

Extended Data Fig. 1 Dislocation morphology of Ti-7Al subjected to 2% of plastic strain using different loading conditions.

a, room temperature without pulsing shows planar dislocation configuration; (b) pulsing deformed showing wavy slip.

Extended Data Fig. 2 Planar dislocation configuration of materials subjected to continuous current.

a, Imaging condition near the basal plane and (b), imaging condition near the {11–23} plane. This Figure illustrates the dislocation structure deformed under continuous current (current density similar to the pulsing deformation reported in the main text). The temperature during deformation is measured to be around 200 °C. It is shown clearly, in two distinctive imaging conditions (A-near the basal plane, and B-near the {11–23} plane), that the dislocation exhibits a planar configuration, indicating a lack of cross-slip and is very similar to the deformation at room temperature. This suggests that raising temperature at this range cannot trigger planar-to-wavy transition.

Extended Data Fig. 3 Dislocation configuration from the as fractured tensile specimen.

a, high density of wavy dislocation tangles in pulsing deformed sample; (b) Planar dislocation bands in sample deformed at room temperature (RT).

Extended Data Fig. 4 Comparison of twinning ability in the different deformation conditions.

EBSD grain boundary misorientation analysis shows that both electrical pulsing and cryogenic deformation temperature lead to an enhanced twinning ability for the Ti-7Al alloy. The field of view of the EBSD scans is 200 µm × 500 µm along the gauge section of the tensile samples.

Extended Data Figure 5 Inverse pole figure mapping of pulsing vs. no-pulsing deformed sample.

It shows virtually no twins in the RT-deformed sample (a), whereas noticeable {10–12} twins are observed in the pulsing-deformed sample.

Extended Data Fig. 6 Secondary electron fractographic micrographs.

a, tensile sample after pulsing deformation and (b) tensile sample without pulsing treatment.

Extended Data Fig. 7 Schematic illustration of dislocation configurations.

a, At room temperature, dislocation prefer to slip on the prismatic plane and cut through the obstacles (Red, solute atoms or short-range order clusters). b, The subsequent dislocations tend to follow the leading dislocation due to slip-plane softening, leading to a planar dislocation configuration similar to what is shown in Fig. 2 (a, b). Note that the obstacles will be destroyed after the passage of several dislocations as each dislocation causes a shear displacement. c, Upon applying a pulsed current, dislocation prefer to cross-slip (shown here on the first order pyramidal plane). d, This mechanism helps dislocations bypass the obstacles, leading to a non-planar dislocation configuration, similar to what is shown in Fig. 2 (c, d).

Extended Data Fig. 8 Detailed illustration of the dog-bone tensile specimen.

a, Schematic drawings of the geometry of the sample mounted in our loading fixture; (b) the CAD model detailed dimension of the dog-bone sample.

Supplementary information

Supplementary Information

Supplementary text.

Supplementary Video 1

Infrared video of the specimen subjected to pulsed and continuous currents.

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Zhao, S., Zhang, R., Chong, Y. et al. Defect reconfiguration in a Ti–Al alloy via electroplasticity. Nat. Mater. 20, 468–472 (2021). https://doi.org/10.1038/s41563-020-00817-z

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