Electron microscope study of Al-Fe-Si intermetallics in 6201 aluminum alloy
- American Racing Equipment Inc., Rancho Dominguez, CA (United States). Aluminum Div.
- McGill Univ., Montreal, Quebec (Canada)
The Al-Fe-Si intermetallics present in a commercial cast 6201 electrical conductor alloy have been studied using high resolution electron microscopy. The {beta}-Al{sub 5}FeSi phase is highly faceted and contains multiple (001) growth twins parallel to the growth direction. The {alpha}-Al{sub 8}Fe{sub 2}Si phase which forms in a Chinese script morphology has a nonfaceted interface with the aluminum matrix and exhibits no growth twinning. Formation of the {beta} phase is believed to occur via a peritectic decomposition of {alpha}-Al{sub 8}Fe{sub 2}Si at 612 C. Observations made by transmission electron microscopy (TEM) support this hypothesis. When 30 ppm strontium is added to this alloy, the {alpha} phase is stabilized and very little {beta}-Al{sub 5}FeSi appears in the microstructure. A silicon-rich layer is found around the {alpha}-phase particles. It is proposed that strontium adsorbs to the {alpha}-phase interface, and in so doing, the diffusion of silicon into the {alpha} phase, necessary for its transformation to {beta}, is prevented.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 250720
- Journal Information:
- Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 4 Vol. 27; ISSN 0360-2133; ISSN MTTABN
- Country of Publication:
- United States
- Language:
- English
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