Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Micrograph 727 and full record

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 <span class="symbol">m</span>m 3 minutes, 1 <span class="symbol">m</span>m 5 minutes, Colloidal silica 10 minutes. Etched using a ‘Nimonic’ etch which preferentially attacks <span class="symbol">g</span>'.
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-NonCommercial-ShareAlike 4.0 International
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