Determination of the Elastic Properties of Au5Sn and AuSn from Ab Initio Calculations

Abstract

Elastic constants of single-crystal Au 5 Sn and AuSn were determined through ab initio calculations to characterize their polycrystalline elastic behavior and elastic anisotropy. The ideal bulk (K = 127 GPa), shear (G = 28 GPa), and YoungÕs modulus (E = 78 GPa), as well as PoissonÕs ratio (v = 0.398), of Au 5 Sn were determined using the Voigt-Reuss-Hill method and were very close to the range of experimental results; the values of AuSn were 88 GPa, 15 GPa, 42 GPa, and 0.420, but its ideal YoungÕs modulus was much smaller than the experimentally obtained values. This unusual discrepancy in the YoungÕs modulus of AuSn is probably attributed to its extraordinarily high anisotropy in YoungÕs modulus, with a 95 GPa difference between its maximum and minimum values. Au 5 Sn exhibits relatively low anisotropy in YoungÕs modulus with a maximum-minimum difference of 38 GPa.

Structural, Elastic, and Electronic Properties of Al-Cu Intermetallics from First-Principles Calculations

“…In previous investigations, firstprinciples calculations have been employed to obtain the structural and elastic properties for a series of intermetallics, such as Cu 6 Sn 5 , Ni 3 Sn, Au 5 Sn, and AuSn, and computation results are in good agreement with experimental data, implying the accuracy of the predictions of this calculation method. [10][11][12] In this work, the structural, elastic, and electronic properties of Al 2 Cu, Al 3 Cu 2 , AlCu, and AlCu 3 intermetallics were calculated by using a firstprinciples method. The calculation results were very close to experimental data.…”

First-Principles Investigations on the Elastic Properties of Platinum Group Metals (Pt, Pd, and Ru)

“…The unit cell was fully optimized in order to obtain the equilibrium crystal structure. Lattice parameters and internal atomic coordinates were independently modified to minimize the total energy and interatomic forces [10]. The strain-stress method was used to obtain elastic constants.…”

“…According to Clarke's model, the phonon mean free path approaches to the average interatomic distance in the primitive cell at the high temperature limit, and the mean sound velocity ν m could be approximated as 0.7(E/ρ) 0.5 . Hence, the minimum thermal conductivity is obtained from the formula (10) , where each symbol has the same meaning as above [28]:…”