Skip to main content

Thank you for visiting 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.

Polyamorphism in a metallic glass


A metal, or an alloy, can often exist in more than one crystal structure. The face-centred-cubic and body-centred-cubic forms of iron (or steel) are a familiar example of such polymorphism. When metallic materials are made in the amorphous form, is a parallel ‘polyamorphism’ possible? So far, polyamorphic phase transitions1,2,3,4,5,6,7 in the glassy state have been observed only in glasses involving directional and open (such as tetrahedral4,5) coordination environments. Here, we report an in situX-ray diffraction observation of a pressure-induced transition between two distinct amorphous polymorphs in a Ce55Al45 metallic glass. The large density difference observed between the two polyamorphs is attributed to their different electronic and atomic structures, in particular the bond shortening revealed by ab initio modelling of the effects of f-electron delocalization8,9,10. This discovery offers a new perspective of the amorphous state of metals, and has implications for understanding the structure, evolution and properties of metallic glasses and related liquids. Our work also opens a new avenue towards technologically useful amorphous alloys that are compositionally identical but with different thermodynamic, functional and rheological properties11 due to different bonding and structural characteristics.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: XRD patterns of the Ce55Al45 metallic glass in a diamond anvil cell.
Figure 2: Specific volume versus pressure for amorphous Ce55Al45.
Figure 3: Comparison of the structure factors for the two amorphous polymorphs of Ce55Al45 at comparable pressures.
Figure 4: Comparison of spin-resolved electron density of states (DOS), obtained for the two amorphous Ce55Al45 phases.


  1. McMillan, P. F. Polyamorphic transformations in liquids and glasses. J. Mater. Chem. 14, 1506–1512 (2004).

    Article  CAS  Google Scholar 

  2. Mishima, O., Calvert, L. D. & Whalley, E. An apparently first-order transition between two amorphous phases of ice induced by pressure. Nature 314, 76–78 (1985).

    Article  CAS  Google Scholar 

  3. Meade, C., Hemley, R. J. & Mao, H. K. High-pressure x-ray-diffraction of SiO2 glass. Phys. Rev. Lett. 69, 1387–1390 (1992).

    Article  CAS  Google Scholar 

  4. Morishita, T. High density amorphous form and polyamorphic transformations of silicon. Phys. Rev. Lett. 93, 055503 (2004).

    Article  Google Scholar 

  5. McMillan, P. F. et al. A density-driven phase transition between semiconducting and metallic polyamorphs of silicon. Nature Mater. 4, 680–684 (2005).

    Article  CAS  Google Scholar 

  6. Katayama, Y. et al. A first-order liquid–liquid phase transition in phosphorus. Nature 403, 170–173 (2000).

    Article  CAS  Google Scholar 

  7. Sen, S., Gaudio, S., Aitken, B. G. & Lesher, C. E. A pressure-induced first-order polyamorphic transition in a chalcogenide glass at ambient temperature. Phys. Rev. Lett. 97, 025504 (2006).

    Article  CAS  Google Scholar 

  8. Soderlind, P. Theory of the crystal structures of cerium and the light actinides. Adv. Phys. 47, 959 (1998).

    Article  CAS  Google Scholar 

  9. Svane, A. et al. Self-interaction-corrected local-spin-density calculations for rare earth materials. Int. J. Quant. Chem. 77, 799–813 (2000).

    Article  CAS  Google Scholar 

  10. Shick, A. B., Pickett, W. E. & Liechtenstein, A. I. Ground and metastable states in gamma-Ce from correlated band theory. J. Electron Spectrosc. Relat. Phenom. 114, 753–758 (2001).

    Article  Google Scholar 

  11. Poole, P. H. et al. Polymorphic phase transitions in liquids and glasses. Science 275, 322–323 (1997).

    Article  CAS  Google Scholar 

  12. O’Keeffe, M. & Navrotski, A. (eds) in Structure and Bonding in Crystals (Academic, New York, 1981).

  13. Lacks, D. J. First-order amorphous-amorphous transformation in silica. Phys. Rev. Lett. 84, 4629–4632 (2000).

    Article  CAS  Google Scholar 

  14. Angell, C. A. Formation of glasses from liquids and biopolymers. Science 267, 1924 (1995).

    Article  CAS  Google Scholar 

  15. Greer, A. L. Metallic glasses. Science 267, 1947 (1995).

    Article  CAS  Google Scholar 

  16. Sheng, H. W. et al. Pressure tunes atomic packing in metallic glass. Appl. Phys. Lett. 88, 171906 (2006).

    Article  Google Scholar 

  17. Jiang, J. Z., Gerward, L. & Olsen, J. S. Comment on “Reversible phase transition between amorphous and crystalline in Zr41.2Ti13.8Cu12.5Ni10Be22.5 under high pressure at room temperature”. Appl. Phys. Lett. 80, 3015–3016 (2002).

    Article  CAS  Google Scholar 

  18. Gschneider, K. A. Jr & Eyring, L. R. (eds) in Handbook on the Physics and Chemistry of Rare Earths (North-Holland, Amsterdam, 1978).

  19. Jayaraman, A. Fusion curve of cerium to 70 kilobar and phenomena associated with supercritical behavior of fcc cerium. Phys. Rev. A 137, 179–182 (1965).

    Article  CAS  Google Scholar 

  20. Almarza, N. G. & Lomba, E. Determination of the interaction potential from the pair distribution function: An inverse Monte Carlo technique. Phys. Rev. E 68, 011202 (2003).

    Article  CAS  Google Scholar 

  21. Johansson, B. Alpha-gamma transition in Cerium is a Mott transition. Phil. Mag. 30, 69–482 (1974).

    Article  Google Scholar 

  22. Maddox, B. R. et al. 4f delocalization in Gd: Inelastic X-ray scattering at ultrahigh pressure. Phys. Rev. Lett. 96, 215701 (2006).

    Article  CAS  Google Scholar 

  23. Falconi, S., Lundegaard, L. F., Hejny, C. & McMahon, M. I. X-ray diffraction study of liquid Cs up to 9.8 GPa. Phys. Rev. Lett. 94, 125507 (2005).

    Article  CAS  Google Scholar 

  24. Errandonea, D., Boehler, R. & Ross, M. Melting of the rare earth metals and f-electron delocalization. Phys. Rev. Lett. 85, 3444–3447 (2000).

    Article  CAS  Google Scholar 

  25. Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).

    Article  CAS  Google Scholar 

  26. Malterre, D., Krill, G., Durand, J., Marchal, G. & Ravet, M. F. Electronic configuration of Ce in amorphous alloys investigated by x-ray absorption spectroscopy. Phys. Rev. B 34, 2176–2181 (1986).

    Article  CAS  Google Scholar 

  27. Dudarev, L. et al. Electron-energy-loss spectra and the structural An LSDA+U study stability of nickel oxide. Phys. Rev. B 57, 1505 (1998).

    Article  CAS  Google Scholar 

  28. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

    Article  Google Scholar 

  29. Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).

    Article  CAS  Google Scholar 

  30. Stillinger, F. H. & Weber, T. A. Packing structures and transitions in liquids and solids. Science 225, 983–989 (1984).

    Article  CAS  Google Scholar 

  31. Soper, A. K. Partial structure factors from disordered materials diffraction data: An approach using empirical potential structure refinement. Phys. Rev. B 72, 104204 (2005).

    Article  Google Scholar 

  32. Sheng, H. W., Luo, W. K., Alamgir, F. M., Bai, J. M. & Ma, E. Atomic packing and short-to-medium range in metallic glasses. Nature 439, 419–425 (2006).

    Article  CAS  Google Scholar 

Download references


This work was supported by US Department of Energy, Office of Science, Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract No. DE-FG02-03ER46056. The APS and HPCAT facilities were supported by DOE-BES, DOE-NNSA (CDAC), NSF, DOD-TACOM and the W. M. Keck Foundation.

Author information

Authors and Affiliations


Corresponding authors

Correspondence to H. W. Sheng or E. Ma.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary figures, references and methods (PDF 5758 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Sheng, H., Liu, H., Cheng, Y. et al. Polyamorphism in a metallic glass. Nature Mater 6, 192–197 (2007).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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