First-principles calculations of β″-Mg5Si6/α-Al interfaces

Y. Wang*, Z. K. Liu, L. Q. Chen, C. Wolverton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

The metastable β″-Mg5Si6 phase is often the most effective hardening precipitate in Al-rich Al-Mg-Si alloys. Two important factors that control the precipitate morphology are the strain energy and the interfacial energy between the precipitate and the matrix. By means of a first-principles supercell approach and density functional theory calculations, we have studied the interfacial properties between β″-Mg5Si6 and α-Al. We carefully construct a large number of interfacial cells in order to elucidate preferred interfacial terminations and orientations, as well as atom alignment and intermixing across the interface. Each of the low-energy interfaces we found possesses two key attributes: a high number of Al-Si bonds across the interface, and a face-centered cubic topological alignment of atoms across those interfaces. Our first-principles results yield quantitative values for the interfacial energies, lattice mismatches and strain energies that can be used in future predictions of precipitate morphologies as a function of size.

Original languageEnglish (US)
Pages (from-to)5934-5947
Number of pages14
JournalActa Materialia
Volume55
Issue number17
DOIs
StatePublished - Oct 2007

Funding

This work is funded by the National Science Foundation (NSF) through Grant DMR-0205232. First-principles calculations were carried out on the LION clusters at the Pennsylvania State University, supported in part by the NSF Grants (DMR-9983532, DMR-0122638, and DMR-0205232) and in part by the Materials Simulation Center and the Graduate Education and Research Services at the Pennsylvania State University. This research also used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. We would also like to thank Dr. Shunli Shang in our Phases Research Lab for stimulating discussions.

Keywords

  • First-principles
  • Interfacial energy
  • Lattice mismatch
  • β″-MgSi/α-Al interface

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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