Microstructure of Ni-Ni3Si eutectic alloy produced by directional solidification

The microstructures and solidification behaviour of Ni-Ni,Si eutectic compo site have been studied systematically. Samples were processed in a Bridgman type solidification furnace using induction heating with growth rates rang ing from 6.5 to 20.0 mm/h. During directional solidification, Ni-Ni3Si eute ctic is characterised by cell and dendrite-free and well-aligned lamellar s tructure on a micron scale. The scaling laws of the variation in lamellar s pacing (lambda) with growth rate (V) are quantitatively developed. Despite the presence of an intermetallic phase, highly regular structure was obtain ed and no lamellar spacing selection problem was observed. (C) 1999 Elsevie r Science B.V. All rights reserved.