The region analyzed is a computer simulated nickel film with a crack propagating through the analysis region. The model, shown in Figure 1, only shows two planes of the atomic structure. The unit cell of the crystal structure is defined by four sublattices, which describe the corners and faces of the FCC structure. Figure 2 shows a unit cell example extracted from a grain in the simulated nickel film. The blue atom represents a corner atom and the red atoms represent the face centers.
Angstroms are the interatomic distances which correspond to the magnitude of sublattice vectors.
The perfect lattice value is 2.49 Angstroms, very close to the measured values from the computer simulation. Using the unit cell shown in Figure 2, the rest of the crystal structure can be completed using symmetry. Figure 3 reveals more about the cubic FCC structure by showing two complete planes of a single cubic FCC crystal and the 45 and 90 degree angles necessary for the cubic classification. There are many grain boundaries, interfacial defects, associated with this nickel film. The boundaries are defined as areas separating two regions of having different crystallographic orientations.