Skip to main content Accessibility help
×
Home

Effect of Alloy Composition on the Structure of Zr Based Metal Alloys

  • B. S. Chao (a1), R. C. YOUNG (a1), S. R. Ovshinsky (a1), D. A. Pawlik (a1), B. Huang (a1), J. S. Im (a1) and B. C. CHAKOUMAKOS (a2)...

Abstract

The structures of Ovonic multi-element, multi-phase Zr-based transition metal alloys for hydrogen storage are studied. The alloys are designed to be multi-phase materials. The hexagonal and diamond cubic structures, known as C14 and C15 Laves structures respectively, are the two major hydrogen storage phases in the alloys. In both C14 and C 15 structures, Zr and Ti are the elements typically occupying the hydride former (A) sites and V, Cr, Mn, Fe, Co and Ni the catalytic (B) sites. Based on the application of Ovshinsky's design principles for disordered materials, both A and B sites are compositionally disordered by the corresponding elements in cubic (C15) structure. However, the hexagonal (C14) structure has two distinct B sites, B(I) and B(Il) with a 1:3 ratio. Preliminary neutron diffraction studies indicate that the B(I) sites are predominantly occupied by Ni and the B(ll) sites are randomly mixed with V, Cr, Mn, Fe, and Ni. It is then proposed that the formula of the hexagonal structure should become A2B(I)IB(II) 3 in the current multi-element Zr-based alloys. Minor phases close to the structures of Zr7Ni10, Zr9Ni11, and ZrO2 are also present in some alloys. The average electron concentration factor (e/a) derived from the alloy composition dictates the alloy structures. The alloys with higher electron concentration factor (> 7.1) favor the diamond cubic structure. On the other hand, the hexagonal structure is associated with the alloys with lower electron concentration factor (< 6.5). The alloys having electron concentration factors in between are mixtures of the diamond cubic and hexagonal structures.

Copyright

References

Hide All
1. Sapru, K., Reichman, B., Reger, A., Ovshinsky, S.R., U.S. Patent 4 623 597 (1986).
2. Ovshinsky, S.R., Fetcenko, M.A., Ross, J., Science 260, 176(1993).
3. Young, R.T., Huang, B., Chao, B.S. and Ovshinsky, S.R., Mater. Res. Soc. Proc. Spring Symp. CC, (1999).
4. Didisheim, J.J., Yvon, K., Shaltiel, D., Fisher, P., Solid State Comm. 31, 47(1979).
5. Fruchart, D., Rouault, A., Shoemaker, C.B., Shoemaker, D.P., J. Less-Comm. Met. 73, 363(1980).
6. Laves, F., Witte, H., Metallwirschaft 14, 645(1935).
7. Laves, F., Witte, H., Metallwirschaft 15, 840(1936).
8. Zhu, J.H., Liaw, P.K., Liu, C.T., Mater. Sci. and Eng. A239–240, 260 (1997).
9. Bardos, D.I., Gupta, K.P., Beck, P.A., Trans. Met. Soc. AIME 221, 1087(1961).
10. Watson, R.E., Bennett, L.H., Acta Metall. 32, 477 and 491 (1984).
11. Periodic Table of the Elements from the Sargent Welch (1998).
12. “Smithell's Metal Reference Book” edited by Brandes, E.A. and Brook, G.B., 7th Edition, Butterworth Heinemann, p. 441 (1998).
13. Chao, B.S. et al., will be published.
14. Bououdina, M., Soubeyroux, J.L., Fruchar, D., de Rango, P., J. Alloys Comp 257, 82 (1997).
15. Yoshida, M.,Akiba, ’ E., J. Alloys Comp 224, 121 (1995).

Effect of Alloy Composition on the Structure of Zr Based Metal Alloys

  • B. S. Chao (a1), R. C. YOUNG (a1), S. R. Ovshinsky (a1), D. A. Pawlik (a1), B. Huang (a1), J. S. Im (a1) and B. C. CHAKOUMAKOS (a2)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed