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Micrograph 727 and full record

Link to image file for micrograph 727
Micrograph no
727
Brief description
Ni-Superalloy, heat treated above gamma-prime solvus
Keywords
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
Heat treated at 1200ºC for one hour, forced air cool.
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
Field emission gun scanning electron microscopy (FEGSEM) in secondary electron imaging (SEI) mode
Length bar
100 nm
Further information
Micrograph shows a close up of the secondary g' present within the centre of g grains. This form of g' grows with prolonged exposure to temperature and forms the blocky primary g' found on the grain boundaries.

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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