Hostname: page-component-848d4c4894-pftt2 Total loading time: 0 Render date: 2024-06-08T19:01:15.944Z Has data issue: false hasContentIssue false

Structure property relationships in the design of alloy composition: Moving beyond electron to atom ratios

Published online by Cambridge University Press:  03 March 2011

M.E. Eberhart*
Affiliation:
Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401
T.E. Jones
Affiliation:
Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401
M.A. Batchelder
Affiliation:
Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401
G.B. Olson
Affiliation:
Department of Materials Science, Northwestern University, Evanston, Illinois 60208-3108
*
a)Address all correspondence to this author. e-mail: meberhart@mines.edu
Get access

Abstract

A model explaining the variability of oxygen solubility in the transition metals is proposed in this article. It assumes that the energy of solution can be represented as the sum of the work required to embed an oxygen atom in the electron gas of the host lattice, plus the energy generated through the formation of an oxygen anion. The latter term is treated as nearly constant across the transition metal series, leaving the work term to account for the observed variations in oxygen solubility. This work, we argue, can be approximated by the ratio of the number of metal electrons excluded from the region around the oxygen atom to the Fermi energy density of states. In turn, the number of electrons excluded by oxygen is assumed to be proportional to the charge density at the octahedral interstitial site. These assumptions allow us to define a solubility parameter that is easily determined with first-principles methods. This parameter is shown to correlate well with experimental findings regarding oxygen solubility in transition metals. Supported by these findings, we use first principle methods to identify alloying elements likely to reduce the solubility of oxygen in niobium.

Type
Articles
Copyright
Copyright © Materials Research Society 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Hume-Rothery, W., Mabbott, G.W. and Channel-Evans, K.M.: The freezing points, melting points, and solid solubility limits of the alloys of silver, and copper with the elements of the B sub-groups. Philos. Trans. R. Soc. A 233, 1 (1934).Google Scholar
2.Hume-Rothery, W. and Raynor, G.V.: The Structure of Metals and Alloys, Monograph No. 1 (Institute of Metals, London, U.K., 1983).Google Scholar
3.Tiwari, G.P. and Ramanujan, R.V.: The relation between the electron to atom ratio and some properties of metallic systems. J. Mater. Sci. 36, 271 (2001).Google Scholar
4.Olson, G.B., Freeman, A.J., Voorhees, P.W., Ghosh, G., Perepezko, J., Eberhart, M., and Woodward, C.: Quest for noburnium: 1300C cyberalloy, in International Symposium on Niobium for High Temperature Applications, edited by Kim, Y-W. and Carneiro, T. (TMS, Warrendale, PA, 2004), pp. 113122.Google Scholar
5.Bryant, R.T.: The solubility of oxygen in transition metal alloys. J. Less-Comm. Metals 4, 62 (1962).Google Scholar
6.Taylo, A. and Doyle, N.J.: The solid-solubility of oxygen in Nb and Nb-rich Nb-Hf, Nb-Mo and Nb-W alloys: Part III. The ternary systems Nb–Mo–O and Nb–W–O. J. Less-Comm. Metals 13, 338 (1967).CrossRefGoogle Scholar
7.Binary Alloy Phase Diagrams, edited by Murray, J., Bennett, L., and Baker, H., (American Society for Metals, Metals Park, OH, 1986).Google Scholar
8.Davenport, J.W.: Linear augmented-Slater-type-orbital method for electronic-structure calculations. Phys. Rev. B 29, 2896 (1984).CrossRefGoogle Scholar
9.Fernando, G.W., Davenport, J.W., Watson, R.E. and Weinert, M.: Full-potential linear augmented–Slater-type-orbital method. Phys. Rev. B 40, 2757 (1989).CrossRefGoogle ScholarPubMed
10.Guerra, C. Fonseca, Snijders, J.G. and Baerends, E.J. te Velde: Towards an order-N DFT method. Theor. Chem. Acc. 99, 391 (1998).Google Scholar
11.van Gisbergen, S.J.A., Snijders, J.G. and Baerends, E.J.J.: Implementation of time-dependent density functional response equation. Comput. Phys. Commun. 118, 119 (1999).Google Scholar