First-principles studies of intrinsic stacking fault energies and elastic properties of Al-based alloys

The intrinsic stacking fault (ISF) energies and elastic properties of pure Al with several common alloying ele-ments (Be, Mg, Sc, Y, Ce) were studied by the first-principles calculations. It was found that Be increased the ISF energy of Al, and other atoms decreased the corresponding ISF energies. The underlying mechanism of the effects alloying atoms on the ISF energies of pure Al was explored from the aspect of electron density distribution involving both qualitative and quantitative analyses. In addition, the elastic properties including bulk modulus (B), shear modulus (G), Young's modulus (E), B/G, Cauchy pressure (C12-C44), Poisson's ratio (upsilon) and anisotropy (A) were calculated to study the mechanical behaviors of the alloyed pure Al. These results can provide theo-retical guidance to the design of Al-based alloys.