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Brittle intermetallic compound makes ultrastrong low-density steel with large ductility

Nature volume 518, pages 77–79 (2015)Cite this article

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Abstract

Although steel has been the workhorse of the automotive industry since the 1920s, the share by weight of steel and iron in an average light vehicle is now gradually decreasing, from 68.1 per cent in 1995 to 60.1 per cent in 2011 (refs 1, 2). This has been driven by the low strength-to-weight ratio (specific strength) of iron and steel, and the desire to improve such mechanical properties with other materials. Recently, high-aluminium low-density steels have been actively studied as a means of increasing the specific strength of an alloy by reducing its density3,4,5. But with increasing aluminium content a problem is encountered: brittle intermetallic compounds can form in the resulting alloys, leading to poor ductility. Here we show that an FeAl-type brittle but hard intermetallic compound (B2) can be effectively used as a strengthening second phase in high-aluminium low-density steel, while alleviating its harmful effect on ductility by controlling its morphology and dispersion. The specific tensile strength and ductility of the developed steel improve on those of the lightest and strongest metallic materials known, titanium alloys. We found that alloying of nickel catalyses the precipitation of nanometre-sized B2 particles in the face-centred cubic matrix of high-aluminium low-density steel during heat treatment of cold-rolled sheet steel. Our results demonstrate how intermetallic compounds can be harnessed in the alloy design of lightweight steels for structural applications and others.

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Figure 1: Precipitation of B2 particles during annealing of cold rolled Fe–10%Al–15%Mn–0.8%C–5%Ni (weight per cent) high-specific-strength steel.
Figure 2: Room-temperature tensile properties of HSSS compared with selected metallic alloys of high specific strength6,7,22,23,24,25,26,27.
Figure 3: Scanning TEM images of HSSS after tensile deformation (0.5% strained) showing interaction of dislocations and B2 particles.

References

  1. Davis, S., Diegel, S. & Boundy, R. Transportation Energy Data Book 32nd edn, 4–17 (Oak Ridge National Laboratory, 2013)

    Google Scholar 

  2. Militzer, M. Materials science: a synchrotron look at steel. Science 298, 975–976 (2002)

    Article  CAS  Google Scholar 

  3. Kim, H., Suh, D. W. & Kim, N. J. Fe-Al-Mn-C lightweight structural alloys: a review on the microstructures and mechanical properties. Sci. Technol. Adv. Mater. 14, 014205 (2013)

    Article  Google Scholar 

  4. Suh, D. W. & Kim, N. J. Low-density steels. Scr. Mater. 68, 337–338 (2013)

    Article  CAS  Google Scholar 

  5. Zargaran, A., Kim, H. S., Kwak, J. H. & Kim, N. J. Effects of Nb and C additions on the microstructure and tensile properties of lightweight ferritic Fe–8Al–5Mn alloy. Scr. Mater. 89, 37–40 (2014)

    Article  CAS  Google Scholar 

  6. Sutou, Y., Kamiya, N., Umino, R., Ohnuma, L. & Ishida, K. High-strength Fe-20Mn-Al-C-based alloys with low density. ISIJ Int. 50, 893–899 (2010)

    Article  CAS  Google Scholar 

  7. Frommeyer, G. & Brüx, U. Microstructures and mechanical properties of high-strength Fe-Mn-Al-C light-weight TRIPLEX steels. Steel Res. Int. 77, 627–633 (2006)

    Article  CAS  Google Scholar 

  8. Gutierrez-Urrutia, I. & Raabe, D. Influence of Al content and precipitation state on the mechanical behavior of austenitic high-Mn low-density steels. Scr. Mater. 68, 343–347 (2013)

    Article  CAS  Google Scholar 

  9. Gschneidner, K., Jr et al. A family of ductile intermetallic compounds. Nature Mater. 2, 587–591 (2003)

    Article  CAS  ADS  Google Scholar 

  10. Kuc, D., Niewielski, G. & Bednarczyk, I. Structure and plasticity in hot deformed FeAl intermetallic phase base alloy. Mater. Charact. 60, 1185–1189 (2009)

    Article  CAS  Google Scholar 

  11. Stoloff, N. S., Liu, C. T. & Deevi, S. C. Emerging applications of intermetallics. Intermetallics 8, 1313–1320 (2000)

    Article  CAS  Google Scholar 

  12. Liu, C. T., Stringer, J., Mundy, J. N., Horton, L. L. & Angelini, P. Ordered intermetallic alloys: an assessment. Intermetallics 5, 579–596 (1997)

    Article  CAS  Google Scholar 

  13. Cao, G. H. et al. Determination of slip systems and their relation to the high ductility and fracture toughness of the B2 DyCu intermetallic compound. Acta Mater. 55, 3765–3770 (2007)

    Article  CAS  Google Scholar 

  14. Davies, R. G. Influence of martensite composition and content on the properties of dual phase steels. Metall. Trans. A 9, 671–679 (1978)

    Article  Google Scholar 

  15. Thomser, C., Uthaisangsuk, V. & Bleck, W. Influence of martensite distribution on the mechanical properties of dual phase steels: experiments and simulation. Steel Res. Int. 80, 582–587 (2009)

    CAS  Google Scholar 

  16. Choi, K. et al. Effect of aging on the microstructure and deformation behavior of austenite base lightweight Fe-28Mn-9Al-0.8C steel. Scr. Mater. 63, 1028–1031 (2010)

    Article  CAS  Google Scholar 

  17. Yoo, J. D. & Park, K. T. Microband-induced plasticity in a high Mn-Al-C light steel. Mater. Sci. Eng. A 496, 417–424 (2008)

    Article  Google Scholar 

  18. Breuer, J., Grün, A., Sommer, F. & Mittemeijer, E. J. Enthalpy of formation of B2-Fe1-xAlx and B2-(Ni,Fe)1-xAlx . Metall. Mater. Trans. B 32, 913–918 (2001)

    Article  Google Scholar 

  19. Chumak, I., Richter, K. W. & Ipser, H. Isothermal sections in the (Fe, Ni)-rich part of the Fe-Ni-Al phase diagram. J. Phase Equil. Diffus. 29, 300–304 (2008)

    Article  CAS  Google Scholar 

  20. Leslie, W. C. The Physical Metallurgy of Steels 43–59 (TechBooks, 1981)

    Google Scholar 

  21. Richeton, T., Weiss, J. & Louchet, F. Breakdown of avalanche critical behaviour in polycrystalline plasticity. Nature Mater. 4, 465–469 (2005)

    Article  CAS  ADS  Google Scholar 

  22. Gil, F. J., Manero, J. M., Ginebra, M. P. & Planell, J. A. The effect of cooling rate on the cyclic deformation of β-annealed Ti-6Al-4V. Mater. Sci. Eng. A 349, 150–155 (2003)

    Article  Google Scholar 

  23. Tähtinen, S., Moilanen, P., Singh, B. N. & Edwards, D. J. Tensile and fracture toughness properties of unirradiated and neutron irradiated titanium alloys. J. Nucl. Mater. 307–311, 416–420 (2002)

    Article  ADS  Google Scholar 

  24. Marmy, P. & Leguey, T. Impact of irradiation on the tensile and fatigue properties of two titanium alloys. J. Nucl. Mater. 296, 155–164 (2001)

    Article  CAS  ADS  Google Scholar 

  25. Bowen, A. W. The influence of crystallographic orientation on tensile behaviour in strongly textured Ti6Al4V. Mater. Sci. Eng. 40, 31–47 (1979)

    Article  CAS  Google Scholar 

  26. Dursun, T. & Soutis, C. Recent developments in advanced aircraft aluminium alloys. Mater. Des. 56, 862–871 (2014)

    Article  CAS  Google Scholar 

  27. Merati, A. in Corrosion Fatigue and Environmentally Assisted Cracking in Aging Military Vehicles (RTO-AG-AVT-140) Ch. 24 (Research and Technology Organization, NATO, 2011)

    Google Scholar 

  28. Fan, D. W., Kim, H. S. & De Cooman, B. C. A review of the physical metallurgy related to the hot press forming of advanced high strength steel. Steel Res. Int. 80, 241–248 (2009)

    CAS  Google Scholar 

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Acknowledgements

We thank J.-S. Lee and Y.-U. Heo for discussions. The press hardening steel was obtained from POSCO. This work was supported by the Steel Innovation Program of POSCO.

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Authors and Affiliations

  1. Graduate Institute of Ferrous Technology, POSTECH, Pohang 790-784, South Korea,

    Sang-Heon Kim, Hansoo Kim & Nack J. Kim

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  1. Sang-Heon Kim
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  2. Hansoo Kim
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  3. Nack J. Kim
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Contributions

N.J.K. and H.K. designed the study; S.-H.K. and H.K. performed the research; S.-H.K., N.J.K. and H.K. analysed the data; and N.J.K and H.K. wrote the paper. All authors discussed the results and commented on the manuscript.

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Correspondence to Hansoo Kim.

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The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Change of X-ray diffraction pattern during annealing at 900 °C.

With the increase in annealing time, the (100) peak of B2 becomes more pronounced owing to its precipitation (samples were water-quenched after annealing). au, arbitrary units.

Extended Data Table 1 Composition of the present HSSS and reference materials
Full size table
Extended Data Table 2 Thermal treatment condition and properties of the present HSSS and reference materials
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Kim, SH., Kim, H. & Kim, N. Brittle intermetallic compound makes ultrastrong low-density steel with large ductility. Nature 518, 77–79 (2015). https://doi.org/10.1038/nature14144

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