Elastic Properties, Mechanical Stability, and State Densities of Aluminnides |

B.R. Zhang
^{a}, Z. Jia^{a}, X.Z. Duan^{b} and X.Z. Yang^{a}^{a}Aviation General Hospital, Beijing, 100012, China
^{b}Beijing Tongren Hospital, Beijing, 100730, China |

Received: July 22, 2012; in final form: February 9, 2013 |

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First-principles calculations were performed to study on alloying stability, electronic structure, and mechanical properties of Al-based intermetallic compounds. The results show that the lattice parameters obtained after full relaxation of crystalline cells are consistent with experimental data. The calculation of cohesive energies indicated that the structure stability of these Al-based intermetallics will become higher with increasing Zr element in crystal. The calculations of formation energies showed that AlCu_{2}Zr has the strongest alloying ability, followed by AlZr_{3} and finally the AlCu_{3}. Further analysis finds out that single-crystal elastic constants at zero-pressure satisfy the requirement of mechanical stability for cubic crystals. The calculations on the ratio of bulk modulus to shear modulus reveal that AlCu_{2}Zr can exhibit a good ductility, followed by AlCu_{3}, whereas AlZr_{3} can have a poor ductility; however, for stiffness, these intermetallics show a converse order. The calculations on Poisson's ratio show that AlCu_{3} is much more anisotropic than the other two intermetallics. In addition, calculations on densities of states indicates that the valence bonds of these intermetallics are attributed to the valence electrons of Cu 3d states for AlCu_{3}, Cu 3d and Zr 4d states for AlCu_{2}Zr, and Al 3s, Zr 5s and 4d states for AlZr_{3}, respectively; in particular, the electronic structure of the AlZr_{3} shows the strongest hybridization, leading to the worst ductility. |

DOI: 10.12693/APhysPolA.123.668 PACS numbers: 31.15.A- |