Composition and solidification microstructure selection in the interdendritic matrix between primary Al{sub 3}Fe dendrites in hypereutectic Al-Fe alloys
- Univ. of Sheffield (United Kingdom). Dept. of Engineering Materials
The composition and constitution of matrix microstructure between plate-like Al{sub 3}Fe dendrites in Bridgman-grown hypereutectic Al-Fe alloys has been determined as a function of alloy concentration C{sub 0} and growth velocity V in the ranges 2.5 < C{sub 0} < 28.1 wt%Fe and 0.01 < V < 5.0 mm/s. The transition at V = 0.1 mm/s from a fully eutectic matrix at C{sub 0} = 3.5 wt%Fe to one containing {alpha}Al dendrites at C{sub 0} {ge} 4.7 wt%Fe is attributed to growth temperatures of {alpha}Al dendrites that are higher than those of eutectic in a matrix of lower iron-content, which results from these conditions. The matrix eutectic changes from irregular {alpha}-Al-Al{sub 3}Fe to regular {alpha}Al-Al{sub x}Fe with increasing V, the transition velocity increasing from 0.1 to 0.2 mm/s for C{sub 0} values of 9.5 and 14 wt%Fe up to 0.35--1.0 mm/s for C{sub 0} values of 18.7--28.1 wt%Fe. This increased transition velocity, compared with that for {alpha}-Al-Al{sub 3}Fe to {alpha}Al-Al{sub 6}Fe at lower concentration, is indicative of a lower formation temperature for the {alpha}Al-Al{sub x}Fe than the {alpha}Al-Al{sub 6}Fe eutectic.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 264114
- Journal Information:
- Acta Materialia, Vol. 44, Issue 7; Other Information: PBD: Jul 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of Cooling Rate on Nano-Eutectic Formation in Laser Surface Remelted and Rare Earth Modified Hypereutectic Al-20Si Alloys
Developing of nano sized fibrous eutectic silicon in hypereutectic Al–Si alloy by laser remelting