Point defects and the binding energies of boron near defect sites in Ni{sub 3}Al: A first-principles investigation
- 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, Vol. 45, Issue 2; Other Information: PBD: Feb 1997
- Country of Publication:
- United States
- Language:
- English
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