Using an embedded-atom model for Ni-Al alloys, we have examined interfacial properties of the Ni/Ni3Al system, concentrating on properties of the antiphase boundaries. These interfaces between domains of the gamma' phase can undergo a pre-wetting transition as the region of the antiphase boundaries disorders and then transforms into a metastable gamma phase. In order to understand more about this transition, we have performed detailed thermodynamic, compositional, and structural analyses of this system using semi-grand canonical Monte-Carlo simulations, with particular interest in composition profiles and segregation. We will discuss our studies in the context of previous treatments of these interfaces.