First-principles calculations of stacking fault and twin boundary energies of Cr2Nb

The stacking fault and twin boundary energies of C15 Cr2Nb are calculated by the first-principles local-density-functional approach. It is found that the intrinsic and extrinsic stacking fault energies are 116 and 94mJ m-2, respectively, and the twin boundary energy is 39 mJ m-2. The lower extrinsic stacking fault energy is consistent with the fact that the C36 structure has a lower energy than the C14 structure. The calculated stacking fault energies at 0 K are larger than the experimental values available in the literature. The equilibrium separations between Shockley partials based on the calculated elastic constants and stacking fault energies are also calculated.