Elastic Property of Cu3Sn Determined by a First-Principles Calculation on the Basis of its Crystal Substructure

As compared with the significance for controlling reliability of solder joints, research on elastic behavior of Cu₃Sn has not been given enough consideration mainly because of the difficulty in preparing acceptable single-phase sample. In this paper, independent elastic constants of single crystal Cu₃Sn are determined from first-principles calculations with a pseudopotential plane-wave method to completely characterize its polycrystalline elastic behavior and elastic anisotropy. The ideal elastic, shear and bulk modulus (E=147GPa, G=56GPa and K=132GPa) as well as the Poisson´s ratio (v=0.315) of Cu₃Sn were predicted by Voigt-Reuss-Hill method. Cu₃Sn exhibited distinct anisotropy in Young´s modulus, as shown by the large difference between maximum and minimum of 44GPa, which may be partially responsible for the discrepancy in the experimental results. The Young´s modulus of Cu₃Sn with texture in real solder joints was also explored.