Site preference and elastic properties of 3d transition metals alloying addition in ductility YAg alloys

摘要

First-principles supercell calculations based on density functional theory were performed to study the site preference behavior and elastic properties of 3d (Ti-Cu) transition-metal elements in B2 ductility YAg alloy. It is found that Ti occupies the Y sublattice, while V, Cr, Co, Fe, Ni and Cu tend to substitute for Ag site. All alloying elements can decrease the lattice parameters of Y_8Ag_8, among which Y_7Ag_8Ti shows the largest change. Furthermore, the calculated elastic constants show that Cr, Fe, Co and Cu can improve the ductility of YAg alloy, and Y_8Ag_7Fe presents the most ductility among these alloy, while Ti and Ni alloying elements reduce the ductility of YAg alloy, especially, V transforms ductile into brittle for YAg alloy. In addition, both V and Ni can increase the hardness of YAg alloy, and Y_8Ag_7V is harder than Y_8Ag_7Ni.