Atomistic simulation of an fcc/bcc interface in Ni-Cr alloys

The embedded atom method is applied to study the atomic structure and energy of an f.c.c./b.c.c. interface in Ni-Cr. The two phases are oriented in a Kurdjumov-Sachs orientation relationship, and the interface considered is the (1(2) over bar1$)(f) habit plane adopted by precipitate laths of the b.c.c. phase. The interfacial energy and coherent strain energy at OK are calculated for boundaries between an f.c.c. Ni-Cr solid solution and b.c.c. Cr. The calculated interfacial energy varies from 216 mJ/m(2) when the f.c.c. phase is pure Ni to 200 mJ/m(2) when the f.c.c. phase is Ni-50 at.% Cr. Atomic relaxations appear limited to atoms in contact with the interphase boundary. Most of the interfacial energy is attributed to the structural difference across the f.c.c./b.c.c. boundary, and the chemical contribution to the energy is estimated to be less than 20% of the total energy. The values of the calculated energies and the widespread occurrence of the (1(2) over bar1$)(f) habit plane in a variety of alloy systems indicate this boundary orientation has a relatively low interfacial energy. (C) 1997 Acta Metallurgica Inc.