First-principles phase-stability study of fcc alloys in the Ti-Al system

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.5055· OSTI ID:7030813

Asta, M; de Fontaine, D ^[1]; van Schilfgaarde, M ^[2]; Sluiter, M ^[3]; Methfessel, M ^[4]

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1. Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720 (United States) Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
2. SRI International, Menlo Park, California 94025 (United States)
3. Lawrence Livermore National Laboratory, Condensed Matter Division (L268), P.O. Box 808, Livermore, California 94550 (United States)
4. Fritz-Haber-Institute, Faradayweg 4-6, 1000, Berlin-33 (Germany)

We present the results of a first-principles study of the composition-temperature phase diagram for fcc-based Ti-Al alloys and the related structural and thermodynamic properties. In the approach taken in this study, local-density-functional theory is combined with the formalism of the cluster-variation method (CVM). In particular, the formation energy, bulk modulus, and atomic volume of metastable fcc Ti, fcc Al, and nine ordered fcc intermetallic Ti-Al compounds have been calculated using the full-potential linear-muffin-tin-orbital method. It is shown how the results of these calculations can be used to obtain a set of volume-dependent effective cluster interactions (ECI's) which parametrize the total energies of fcc-based Ti-Al alloys. We discuss in detail how these parameters can be used to determine formation energies, atomic volume, and bulk moduli for both ordered and disordered alloys, and as an example we calculate these properties for alloys containing random distributions of Ti and Al atoms as a function of composition. Furthermore, these ECI's are used in conjunction with the CVM to calculate the solid-state, fcc, composition-temperature phase diagram.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7030813
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:9; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
CLUSTER MODEL
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIAGRAMS
FCC LATTICES
MATHEMATICAL MODELS
NUCLEAR MODELS
PHASE DIAGRAMS
PHASE STABILITY
PHYSICAL PROPERTIES
STABILITY
THERMODYNAMIC PROPERTIES
TITANIUM ALLOYS