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Full Record for Micrograph 725

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Micrograph no
725
Brief description
Ni-Superalloy, as-extruded microstructure
Keywords
extrusion Link to MATTER Glossary entry for extrusion, nickel
Categories
Metal or alloy
System
Ni-X
Composition
Ni, Cr 14.4-15.2, Co 13-18, Mo 3.5-4.5, Al 3.0-3.3, Ti 4.2-4.8, Ta 2.5, Zr 0.05-0.07, C 0.05, B 0.01-0.03 (wt%) (Ni-Superalloy)
Standard codes
Reaction
Processing
Extruded at 1100ºC with a 5.5:1 reduction in area
Applications
Discs are used for high pressure and intermediate pressure turbine discs in Trent 800/900 series gas turbine engines.
Sample preparation
Ground to 4000 Grade SiC paper and then polished at 6 mm 3 minutes, 1 mm 5 minutes, Colloidal silica 10 minutes. Etched using a ‘Nimonic’ etch which preferentially attacks g'.
Technique
Scanning electron microscopy (SEM) in backscattered electron imaging (BEI) mode
Length bar
10 μm
Further information
Micrograph shows a fully recrystallized microstructure containing many equiaxed grains and g' precipitates. In addition to this there are also several carbides and borides (seen as white). There is evidence of misorientation between adjacent grains, demonstrated by the large degree of contrast.

View schematic diagram of g' microstructure
Contributor
R J Mitchell
Organisation
Rolls-Royce University Technology Centre, Department of Materials Science and Metallurgy, University of Cambridge
Date
05/03/03
Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
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