Ab initio calculation of the phase stability, mechanical properties and electronic structure of ZrCr₂ Laves phase compounds

Abstract

Ab initio calculations have been used to investigate the phase stability, mechanical properties and electronic structure of ZrCr₂ Laves phase compounds, based on the method of augmented plane waves plus local orbitals with the generalized gradient approximation. The calculated lattice constants for the C15, C36 and C14 structures are in good agreement with experimental values. The calculation of heats of formation showed that C15 is a ground-state phase, whereas C36 is an intermediate phase and C14 the high-temperature phase. The elastic constants and elastic moduli for the C15 structure were calculated systematically and compared with experiments and previous theoretical calculations. The intrinsic and extrinsic stacking fault energies are found to be 112 and 98 mJ m⁻², respectively. The equilibrium separations between Schockley are also predicted using the calculated elastic moduli and stacking fault energies. Finally, the calculated electronic structures of these Laves phases are discussed based on these results.

Acknowledgements

J. Sun is grateful to Prof. David J. Smith for supporting his visiting the Center for Solid State Science, Arizona State University. B. Jiang acknowledges support from DOE DE-FG03-02ER45596. We also thank Prof. David J. Smith and Prof. J. C. H. Spence for useful discussions. This research was sponsored by the National Natural Science foundation of China (project number 50271040).