Point defects and the binding energies of boron near defect sites in Ni{sub 3}Al: A first-principles investigation

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(96)00208-X· OSTI ID:455251

Fu, C L; Painter, G S ^[1]

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1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

First-principles local-density-functional calculations have been used to investigate the equilibrium point defect structure and boron-defect interactions in Ni{sub 3}Al. The dominant point defect types in off-stoichiometric Ni{sub 3}Al are substitutional antisite defects on both sublattices. The boron binding energy is dependent on lattice coordination; it is strongest near vacancy sites with a nearest-neighbor nickel coordination number of about four (instead of six as in the defect-free interstitial site) and with no aluminum atom nearest-neighbors. This suggests that boron tends to segregate to open defect sites and to enhance cohesion through the formation of localized Ni-B covalent bonds. Comparison of the binding energies of boron and carbon in Ni{sub 3}Al shows that boron has a stronger tendency to segregate to open sites than carbon.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 455251
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 2 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BINDING ENERGY
BORON
DOPED MATERIALS
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
NICKEL ALLOYS
POINT DEFECTS
THEORETICAL DATA
VACANCIES