Interatomic bonds and the tensile anisotropy of trialuminides in the elastic limit: A density functional study for Al<sub>3</sub>(Sc,Ti,V,Cr) - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Philosophical Magazine Année : 2007

Interatomic bonds and the tensile anisotropy of trialuminides in the elastic limit: A density functional study for Al3(Sc,Ti,V,Cr)

Résumé

The tensile anisotropy in the elastic limit of Al3(Sc,Ti,V,Cr) intermetallic compounds in both L12 and D022 crystal structure have been investigated using first-principles density-functional calculations. In both both crystal structures the main bonding character comes from the saturation of dominant d3 (L12) and d4 (D022) hybrid orbitals located on the TM atoms. The series Al3Sc → Al3V corresponds to the gradually d-band filling and leads to a gradual increase of bond-strength and covalent bond formation. The magnetism of Cr breaks this trend in the Al3Cr compound (for both ferromagnetic and anti-ferromagnetic configurations). In this series, a trend towards an increased anisotropy of the elastic constants, Young modulus Y and Poisson ratio ν is observed. The easy and hard directions of tension can be simply identified by the variation of Y, which corresponds to the presence or absence of covalently bonded -Al-TM- chains. A high anisotropy of Poisson ratio arises also from an alternation of atoms in the lateral directions and can be understood in the same terms.

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Dates et versions

hal-00513800 , version 1 (01-09-2010)

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Michal Jahnatek, Marian Krajci, Juergen Hafner. Interatomic bonds and the tensile anisotropy of trialuminides in the elastic limit: A density functional study for Al3(Sc,Ti,V,Cr). Philosophical Magazine, 2007, 87 (11), pp.1769-1794. ⟨10.1080/14786430601057946⟩. ⟨hal-00513800⟩

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