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

Intermetallic matrix composites (IMCs) offer attractive properties, such as high toughness of the metal coupled with low density, high modulus and hig h strength of the intermetallics. Among a large number of the intermetallic s, 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 sol idification of the eutectic alloys as a concept of reinforcing intermetalli cs with in situ refractory metals. The present study is related to the stud y of the eutectic alloys in the ternary NiAl-V system. The eutectic composi tion and temperature were accurately determined. It was concluded that the solidification behaviour of the Ni-Al-V eutectic is strongly dependent on t he growth conditions, namely growth rate and orientation, and that it can b e easily modified. Also, it was observed that the orientation of the grain, i.e., the direction of growth is the determining factor in the lamellar/ro d transition as well as in the morphology of the degenerated structure. (C) 2000 Elsevier Science B.V. All rights reserved.