Solid solution softening in bcc Mo alloys

Effect of transition-metal additions on dislocation structure and mobility

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

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The electronic origin of solid solution softening (SSS) in bcc molybdenum alloys was investigated in the framework of a combined approach that includes atomistic dislocation modeling with first principles parametrization of interatomic interactions. The softening additions are found to locally change the chemical bonding which results in a decrease of the generalized stacking fault (GSF) energy and atomic row shear resistance. Using the atomic row model, we show that the isotropic core of the screw dislocation in Mo tends to a "split" (planar) core under alloying with softener solutes (Re, Os, Ir, Pt). The generalized Peierls-Nabarro model for a non-planar core was employed to link the reduction in GSF energy with the enhancement of double kink nucleation and dislocation mobility. Our study appears to explain the experimental dependence of the alloying effect on the atomic number of the addition and to provide an understanding of the electronic reasons for SSS in Mo alloys.

Original languageEnglish
Article number134107
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume72
Issue number13
DOIs
Publication statusPublished - Oct 1 2005

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Stacking faults
Alloying
softening
Transition metals
Solid solutions
stacking fault energy
solid solutions
transition metals
Molybdenum alloys
Screw dislocations
alloying
molybdenum alloys
Nucleation
screw dislocations
electronics
solutes
nucleation
shear
augmentation
interactions

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Solid solution softening in bcc Mo alloys : Effect of transition-metal additions on dislocation structure and mobility. / Medvedeva, N. I.; Gornostyrev, Yu N.; Freeman, Arthur J.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 72, No. 13, 134107, 01.10.2005.

Research output: Contribution to journalArticle

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