The intrinsic stacking-fault energy of copper under volumetric, longitudinal and shear strains was investigated using density functional theory. Calculations were performed using a copper slab model aligned perpendicular to the (111) intrinsic stacking fault plane. The calculated stacking-fault energy for unstrained copper was 41mJ/m2. The results revealed a strong dependence of stacking-fault energy on strain, and different behaviors for differing types of strain: volumetric and longitudinal in the direction perpendicular to the stacking fault, longitudinal parallel to the stacking fault and shear parallel to the stacking fault. In the first case, the stacking-fault energy decreased monotonically with strain with a slope of -0.44J/m2 and -0.87J/m2 for volumetric and longitudinal, respectively. For the case of shear parallel to the stacking fault, the stacking-fault energy was nearly constant at small and moderately large strains, but fell rapidly at very large strains. For high [11¯2]{111} shear strains, the stacking-fault energy could either increase or decrease at large strains, depending upon the sign of the strain. In volumetric or longitudinal (perpendicular to the stacking fault) tension and longitudinal strain in the boundary plane (and for some shear directions), the stacking-fault energy could become negative; implying a limit on the stability of the fcc crystal structure.

Effect of Strain on the Stacking Fault Energy of Copper: a First-Principles Study. P.S.Branicio, J.Y.Zhang, D.J.Srolovitz: Physical Review B, 2013, 88[6], 064104