The embedded atom model was utilized to study the atomic displacements and the energy of (111) interfaces in Ni-Au and Ni-Pt bicrystals. A sphere of 459 atoms was utilized with the Ni (111) surface as a great circle through the crystal. The Au or Pt atoms were initially placed in perfect registry with the Ni atoms and then the crystal was allowed to relax to equilibrium positions. Shockley partial dislocations formed at the interface. The elastic strains were not in agreement with classical elasticity calculations. The simulation shows that it is easier to pull atoms apart than to push them together; and thus the larger gold lattice was strained less than the smaller nickel lattice even though the elastic modulus of nickel is greater than that of gold.
The Ni and Pt crystals exhibited strong bonding at the interface; whereas, the Ni and Au crystals exhibited little evidence of interface bonding. This result is in agreement with alloy heats of solution and the phase diagrams of these alloys.