Growth and microstructure evolution of the Nb{sub 2}Al-Al{sub 3}Nb eutectic in situ composite

Journal Article · Tue Mar 15 04:00:00 EST 2005 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2004.08.017· OSTI ID:20748738

Rios, C T ^[1]; Ferrandini, P L ^[2]; Milenkovic, S ^[1]; Caram, R ^[1]

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1. State University of Campinas, P.O. Box 6122, Campinas, SP 13083-970 (Brazil)
2. Centro Universitario da FEI, C.P.85, CEP:09850-901, SP-Brasil (Brazil)

In situ composite materials obtained by directional growth of eutectic alloys usually show improved properties, that make them potential candidates for high temperature applications. The eutectic alloy found in the Al-Nb system is composed of the two intermetallic phases Al{sub 3}Nb (D0{sub 22}) and Nb{sub 2}Al (D8{sub b}). This paper describes the directional solidification of an Al-Nb eutectic alloy using a Bridgman type facility at growth rates varying from 1.0 to 2.9 cm/h. Longitudinal and transverse sections of grown samples were characterized regarding the solidification microstructure by using optical and scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction. Despite both phases being intermetallic compounds, the eutectic microstructure obtained was very regular. The results obtained were discussed regarding the effect of the growth rate on the microstructure, lamellar-rod transition and variation of phase volume fraction.

• OSTI ID: 20748738
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 3 Vol. 54; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRYSTAL GROWTH
EUTECTICS
EVOLUTION
GROWTH
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
RODS
SCANNING ELECTRON MICROSCOPY
SOLIDIFICATION
SPECTROSCOPY
VARIATIONS
X-RAY DIFFRACTION