Full Record for Micrograph 726
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- Micrograph no
- Brief description
- Ni-Superalloy, heat treated above gamma-prime solvus
- heat treatment , nickel
- Metal or alloy
- 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
- Heat treated at 1200ÂºC for one hour, forced air cool.
- 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 â€˜Nimonicâ€™ etch which preferentially attacks <span class="symbol">g</span>'.
- Scanning electron microscopy (SEM) in backscattered electron imaging (BEI) mode
- Length bar
- 10 μm
- Further information
- Micrograph shows a microstructure now devoid of g' as at this temperature it has become fully dissolved into the matrix. This results in grain growth, partly due to the solution of g' into the g matrix and also because the main mechanism for preventing grain growth, namely the primary g' is no longer present. Carbide phases still exist and act in places to inhibit grain boundary motion and therefore grain growth.
View schematic diagram of g' microstructure
- R J Mitchell
- Rolls-Royce University Technology Centre, 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 724: Ni-Superalloy, as-extruded microstructure (10 μm)
- Micrograph 725: Ni-Superalloy, as-extruded microstructure (10 μm)
- Micrograph 727: Ni-Superalloy, heat treated above gamma-prime solvus (100 nm)
- Micrograph 728: Ni-Superalloy, heat treated above gamma-prime solvus (10 μm)
- Micrograph 729: Ni-Superalloy, exposed microstructure (10 μm)
- Micrograph 734: Ni-Superalloy, as-extruded microstructure (20 μm)