Calculation and Simulation of the Ground State Properties of Copper-Nickel Alloys

In radiation damage research, copper, nickel, and their alloys are widely used model systems for face-centered-cubic (FCC) metals. The ground-states properties of the ordered and disordered alloys are studied by using the molecular dynamics (MD) and first-principles calculations. For copper-nickel alloys, the equilibrium properties have been predicted by large-scale atomic/molecular massively parallel simulator (LAMMPS), Abinit and WIEN2k, thermodynamics is calculated by LAMMPS and Abinit. In order to investigate the disordered alloys, special quasirandom structures (SQS) and fractional function are adopted in LAMMPS, and their capabilities are demonstrated to predict the properties of disordered alloys. For both the ordered and disordered alloys, the lattice constants in agreement with the Vegard's law are predicted and the bulk moduli present the deviations with respect to the experimental values; with the increasing weight concentration of nickel, the equilibrium volumes reduce and the bulk moduli increase. The calculated cohesive energy of copper and nickel are consistent with the experimental values; the cohesive energies of ordered alloys are predicted. The energies of formation of disordered alloys are always lower than those of ordered alloys.