First-principles calculations of beta"-Mg(5)Si(6)/alpha-Al interfaces

作者：Wang Y^*; Liu Z K; Chen L Q; Wolverton C

来源：Acta Materialia, 2007, 55(17): 5934-5947.

DOI：10.1016/j.actamat.2007.06.045

• beta" -Mg(5)Si(6)/alpha-Al interface
• interfacial energy
• lattice mismatch
• first-principles

The metastable beta ''-Mg(5)Si(6) 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 beta ''-Mg(5)Si(6) and alpha-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.

• 出版日期2007-10