First-principles calculations on Al/AlB2 interfaces

• DOI: 10.1016/j.apsusc.2011.04.038
• Publication Date: 2011-04-18T18:51:27Z
• Authors: Y.F. Han; Y.B. Dai; J. Wang; D. Shu; B.D. Sun
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract The AlB 2 (1 1 1) surfaces and Al (1 1 1)/AlB 2 (0 0 0 1) interface were studied by first-principles calculations to clarify the heterogeneous nucleation potential of α-Al grains on AlB 2 particles in purity aluminium and hypoeutectic Al–Si alloys. It is demonstrated that the AlB 2 (0 0 0 1) surface models with more than nine atomic layers exhibit bulk-like interior, wherein the interlayer relaxations localized within the top three layers are well converged. The outmost layer of AlB 2 free surface having a preference of metal atom termination is evidenced by surface energy calculations. With Al atoms continuing the natural stacking sequence of bulk AlB 2 , Al–Al metallic bonds are formed across interface during the combination of Al atoms with Al-terminated AlB 2 surface. The calculated interfacial energy of the Al/AlB 2 interface is much larger than that between the α-Al and aluminium melts, elucidating the poor nucleation potency of α-Al grains on AlB 2 particles from thermodynamic considerations.