First-principles calculations were performed in order to investigate the defects, mechanical properties and electronic structure of MCr2 (M = Nb, Ti or Zr) Laves phases. The results showed that the ternary addition of V preferentially substituted at the Cr site and Zr at the Nb site in NbCr2. Here, W had a weak site preference on the Cr site in NbCr2. The ternary site substitutions were related to the electronic structure of NbCr2. Further calculations of the densities of states and charge density distribution of TiCr2 showed that a strong covalent bonding between the small atoms (Cr) along the Kagome net formed a tetrahedral electronic network, which was a common feature of the electronic structure of Laves phases. Mechanical properties, such as elastic constants, elastic moduli and stacking-fault energies of ZrCr2, were also calculated. The intrinsic and extrinsic stacking-fault energies of ZrCr2 were found to be 112 and 98mJ/m2, respectively.

First-Principles Studies of Defects, Mechanical Properties and Electronic Structure of Cr-Based Laves Phases. Q.Yao, J.Sun, D.Lin, S.Liu, B.Jiang: Intermetallics, 2007, 15[5-6], 694-9. See also: Chinese Journal of Nonferrous Metals, 2006, 16[7], 1166-70