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First-principles all-electron theory of atomic short-range ordering in metallic alloys: D022- versus L12-like correlations
Physical Review B (1994)
  • Duane D. Johnson, Sandia National Laboratories
  • J. B. Staunton, University of Warwick
  • F. J. Pinski, University of Cincinnati
Abstract
We use a ‘‘first-principles’’ concentration-wave approach based on a finite-temperature, electronic density-functional, mean-field, grand potential of the random alloy to investigate the high-temperature atomic short-range order (ASRO) in Ni75V25 and Pd75V25 solid solutions. Experimentally, these similar alloys both develop D022-type long-range order at low temperatures but different ASRO at high temperatures. Our calculations describe the measured ASRO well. We compare these results with those found for a hypothetical Co75Ti25 solid solution. Since this alloy orders directly from the melt into the L12 phase, it should exhibit strong L12-like ASRO, as we find in our calculations. We analyze the features in the calculated diffuse intensities in terms of various factors in each alloy’s electronic structure. Because we have assumed that the atoms are fixed to the Bravais lattice, we discuss two additional examples, Al75Ti25 and Ni50Pt50, to show the limitations of neglecting atomic displacements. Notably, the Onsager cavity fields have been incorporated into the theory to conserve the diffuse scattering intensity over the Brillouin zone and to provide a better description of the long-ranged, electrostatic screening effects.
Publication Date
July 15, 1994
Publisher Statement
Copyright 1994 American Physical Society
Citation Information
Duane D. Johnson, J. B. Staunton and F. J. Pinski. "First-principles all-electron theory of atomic short-range ordering in metallic alloys: D022- versus L12-like correlations" Physical Review B Vol. 50 Iss. 3 (1994)
Available at: http://works.bepress.com/duane_johnson/69/