Solute Effects on β-Sn Grain Boundary Energy and Shear Stress

Abstract

The excess enthalpy and shear strain behavior of the β-Sn (101) grain boundary containing various amounts of Ag and Cu solute atoms was investigated using molecular simulation. An increase in either type of solute at the interface lowers the excess enthalpy of the grain boundary. The enthalpies of segregation for both solute types are computed as the slope of excess enthalpy of the grain boundary per area versus interfacial solute concentration per area. For Ag, ΔHSEG=0.64(9) eV/atom , and for Cu, ΔHSEG=0.45(8) eV/atom , indicating a preference for grain boundary segregation. These results agree with other simulation work that attributes a larger decrease in grain boundary energy to a solute with a larger atomic radius. A (301) special boundary of β-Sn was also investigated and found ΔHSEG=0.12(9) eV/atom for Ag and ΔHSEG=0.06(9) eV/atom for Cu. Statistically, this shows the possibility for excess enthalpy increase when Cu is present at the (301) boundary. Under constant shear strain, addition of solu...