Structural properties, electronic structure, Fermi surface, and mechanical behavior of bcc Cr-Re alloys

N. I. Medvedeva, Yu N. Gornostyrev, Arthur J Freeman

Research output: Contribution to journalArticle

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Abstract

The electronic structure and ground-state properties (lattice parameter, cohesive energy, bulk and tetragonal shear moduli) were calculated for bcc Cr and Cr-Re alloys over a wide range of Re concentration by the full-potential linear muffin-tin orbital method (FLMTO) with generalized gradient approximation (GGA). We show that the GGA predicts the commensurate antiferromagnetic Cr state as a ground state for the experimental volume with a small lower energy compared with the nonmagnetic state, but gives a large moment of 0.92 μB. In the Cr-Re system the magnetism becomes weak with Re concentration and for 25% Re the mean Cr moment is about 0.05 μB. Examining the Fermi surface of Cr-Re alloys within the modified rigid-band approximation, the electronic topological transition (ETT) is found to occur for 6% Re. A weakening of the Cr-Cr bonds near this ETT is considered as a possible microscopic reason for the "small" rhenium effect - the ductility enhancement in Cr(Mo,W)-Re alloys with small Re additions. As the mechanism for the "large" rhenium effect (near 25-35% Re) the formation of Cr-Re close-packed particles should play an important role together with the significantly weakened Cr-Cr bonding.

Original languageEnglish
Article number134204
Pages (from-to)1342041-1342047
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume67
Issue number13
Publication statusPublished - Apr 2003

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Fermi surface
Rhenium
Fermi surfaces
Electronic structure
Structural properties
rhenium
electronic structure
Ground state
approximation
moments
gradients
ground state
Tin
Magnetism
ductility
electronics
Lattice constants
Ductility
lattice parameters
tin

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Structural properties, electronic structure, Fermi surface, and mechanical behavior of bcc Cr-Re alloys. / Medvedeva, N. I.; Gornostyrev, Yu N.; Freeman, Arthur J.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 67, No. 13, 134204, 04.2003, p. 1342041-1342047.

Research output: Contribution to journalArticle

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