Influence of the growth rate on the microstructure of a Nb–Al–Ni ternary eutectic

• Published in: Journal of crystal growth Vol. 237; pp. 90 - 94
• Main Authors: Rios, Carlos Triveño, Milenkovic, Srdjan, Gama, Sergio, Caram, Rubens
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2002
• Subjects: A1. Directional solidification; A1. Eutectics; A2. Bridgman technique; A2. Growth from melt; A2. Bridgman technique; A1. Eutectics; A1. Directional solidification; A2. Growth from melt
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(01)01873-5

Solidification of a eutectic alloy from the melt produces composite materials, composed of two or more solid phases. Processing by directional solidification presents interesting and different properties when compared to the properties of its constituent phases. One of the ternary systems that has been little studied and exhibits eutectic reaction resulting in three intermetallic phases is the Nb–Al–Ni ternary system, which involves the NbAl
3, Nb
2Al and AlNbNi phases. Eutectic alloys from this system were processed in an arc melting furnace and in a Bridgman equipment for directional growth. The objective of the experiments was to determine the influence of growth parameters on the eutectic microstructure. The mechanical behavior of the composite was studied through microhardness testing and fracture toughness using Vickers indentation technique. Microstructural characterization and chemical compositions of the samples were investigated by using optical and scanning electron microscopy with energy dispersive spectroscopy.