Directional solidification processing of eutectic alloys in the Ni-Al-V system

Intermetallic matrix composites (IMCs) o!er attractive properties, such as high toughness of the metal coupled with low density, high modulus and high strength of the intermetallics. Among a large number of the intermetallics, a particular interest has been shown in the NiAl intermetallic compound, since it exhibits several advantages over the currently used nickel-based superalloys. Recently, there has been a renewed interest in directional solidi"cation of the eutectic alloys as a concept of reinforcing intermetallics with in situ refractory metals. The present study is related to the study of the eutectic alloys in the ternary NiAl}V system. The eutectic composition and temperature were accurately determined. It was concluded that the solidi"cation behaviour of the Ni}Al}V eutectic is strongly dependent on the growth conditions, namely growth rate and orientation, and that it can be easily modi"ed. Also, it was observed that the orientation of the grain, i.e., the direction of growth is the determining factor in the lamellar/rod transition as well as in the morphology of the degenerated structure