Elastic properties and stacking fault energies of Cr2Ta

The elastic moduli, stacking fault and twin boundary energies of C15 Cr2Ta are calculated by first-principles local-density-functional approach. Similarly to the case of Cr2Nb, Cr2Ta is characterized by a low twin boundary energy (33 mJ/m 2 ). On the other hand, the intrinsic and extrinsic stacking fault energies are found to be 88 and 83 mJ/m 2 , respectively. Using the results of elastic constants and stacking fault energies, we predict the equilibrium separation between Shockley partials. The results of Cr2Ta are compared with those of Cr2Nb. # 1999 Elsevier Science Ltd. All rights reserved.