Temperature dependent lattice misfit and coherency of Al3X (X=Sc, Zr, Ti and Nb) particles in an Al matrix

The lattice coherency and critical radii for Al3X precipitates in an aluminum matrix were computed using first-principles methods. From density functional perturbation theory and the quasi-harmonic approximation, the unit cell parameters as a function of temperature were determined for Al3Sc, Al3Zr,...

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Bibliographic Details
Published in:Acta materialia 2015-05, Vol.89, p.109-115
Main Authors: Saha, Saumitra, Todorova, T.Z., Zwanziger, J.W.
Format: Article
Language:English
Subjects:
Aluminum
Aluminum alloys
Coherence
Density functional theory calculations
Intermetallic compounds
Intermetallics
Lattice coherency
Lattices
Mathematical analysis
Mathematical models
Phases
Titanium aluminides
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Summary:The lattice coherency and critical radii for Al3X precipitates in an aluminum matrix were computed using first-principles methods. From density functional perturbation theory and the quasi-harmonic approximation, the unit cell parameters as a function of temperature were determined for Al3Sc, Al3Zr, Al3Ti, and Al3Nbin the L12structure, and for Al3Tiand Al3Nbin their more stable DO22structures. From these data the lattice misfit and critical radii were determined. It was found that Al3Scand Al3Zrbehave similarly, with increasing critical radii and decreasing misfit as a function of temperature, while Al3Tiand Al3Nbbehaved oppositely. Furthermore, the DO22phases showed uniformly poor lattice coherence and very small critical radii. Superior alloy properties in Al/Al3X systems are suggested to require stabilization of the L12phase in the precipitated particles.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2015.02.004