In accordance with the orientation relation (110),<001>β || (111),<110> α, established by the fast electron diffraction method between ordered (β) and disordered (α) phases in the Pd – 57 at .% Cu solid solution foil , the atomic structure of the interface is modeled by molecular dynamics. It is found that the structural and dimensional mismatch is compensated by interfacial dislocations with Burgers vectors a / 2 <111> in β-phase coordinates.