First principle study of electronic structure and mechanical properties of Zr doped Al 2 Cu

Abstract

First principle calculations are adopted using the pseudopotential plane wave method scheme to investigate the electronic structure and mechanical properties of Zr doped Al–Cu intermetallic compounds Al₂Cu. Replacing an Al atom or a Cu atom with a Zr atom, this compound forms the crystal structure of Al₁₅Cu₈Zr or Al₁₆Cu₇Zr. The results show that the structural stability and alloying ability of doped structures are larger than Al₂Cu. Moreover, the structural stability and alloying ability of Al₁₅Cu₈Zr are higher than that of Al₁₆Cu₇Zr. This indicates that Zr is preferred to replace the position of Al. The mechanical properties of doped structures are increased, such as stiffness and plasticity. However, the ductility decreases, and the corresponding room temperature brittleness becomes larger. Theoretical analysis reveals that these two compounds have strong hybridisation between Al s, p states and Zr d states, which leads to intensify the atomic interaction. Therefore, chemical bonds show a character of covalent bond, and the ductility reduces.