Full Record for Micrograph 158
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- Micrograph no
- Brief description
- Roll-bonded aluminium alloy diffusion couple in the as-rolled condition.
- alloy , aluminium , diffusion couple , metal, roll-bonding
- Metal or alloy
- Al, Fe 0.5, Mn 1.0 / Al, Si 1.0 (wt%)
- Standard codes
- Mechanical roll-bonding; reduction in thickness of about 90%.
- The couple was made to investigate diffusion of silicon through the Al-0.5Fe-1.0Mn (wt.%) alloy during annealing.
- Sample preparation
- Electrolytically etched using Barker's reagent.
- Cross-polarised light microscopy
- Length bar
- 400 μm
- Further information
- This micrograph shows the grain structure of a roll-bonded aluminium alloy diffusion couple in the as-rolled condition. The upper half of the couple is Al-0.5Fe-1.0Mn (wt.%), the lower half is Al-1.0Si (wt.%). Rolling heavily deforms the microstructure, producing thin, elongated grains parallel to the roll-bonded interface.
The Barker's etch produces a thick oxide layer on the grains of aluminium (anodising). When viewed in cross-polarised light, interference in the oxide layer produces colours which depend on grain orientation, hence the grain structure is imaged. Prior to roll-bonding the Al-Si alloy was solution-treated, creating recrystallized grains that were much larger than the cellular microstructure of the Al-Fe-Mn alloy. This difference in scale of microstructure can be seen in the rolled diffusion couple.
- D T L Alexander
- Department of Materials Science and Metallurgy, University of Cambridge
- Licence for re-use
- Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
- Related micrographs
- Micrograph 156: Roll-bonded aluminium alloy diffusion couple annealed for 30 minutes at 600ÂºC. (400 μm)
- Micrograph 157: Roll-bonded aluminium alloy diffusion couple annealed for 60 minutes at 600ÂºC. (750 μm)
- Micrograph 159: Roll-bonded aluminium alloy diffusion couple in the as-rolled condition. (2 mm)