First-principles calculations of structural and mechanical properties of Cu_6Sn_5

摘要

The elastic constants of polycrystalline Cu_6Sn_5—an intermetallic in lead-free alternatives of several material systems—are presented. The results are obtained by applying: (ⅰ) Reported crystallographic structure of monoclinic single crystal Cu_6Sn_5, (ⅱ) structure optimization and determination of single crystal elastic constants from first principle calculations, and (ⅲ) limit analysis of polycrystal stiffness based on single crystal properties. The agreement between the calculated Young's modulus (120 GPa) and those from nanoindentation experiments (112-125 GPa), and the tight bounds on the predicted polycrystal values give a measure of confidence in other calculated properties for which experimental data are unavailable.