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Atomic Site Occupancy of Platinum Group Metals in the γ’ (Ll2) Phase of a γ-γ’ Complex Nickel Base Superalloy Using Alchemi (Atomic Location by Channnelling Enhanced Microanalysis)

Published online by Cambridge University Press:  02 July 2020

A. P. Ofori
Affiliation:
Department of Materials Science & Metallurgy, University of Cambridge, New Museums Site, Pembroke Street, CambridgeCB2 3QZ, UK.
C. J. Humphreys
Affiliation:
Department of Materials Science & Metallurgy, University of Cambridge, New Museums Site, Pembroke Street, CambridgeCB2 3QZ, UK.
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Abstract

Nickel-base superalloys (NBSAs) have remarkable mechanical properties (and corrosion resistance) at elevated temperatures. Single crystal NBSAs have found major use as turbine blades in aeroengines, where there is a large world market because the turbine blades have to be replaced at regular intervals. in order to develop engines with higher efficiency, considerable efforts are being devoted to enhance the temperature capabilities of superalloys. The two phase γ-γ’ structure that is crucial to NBSA characteristics is primarily produced by the presence of Al in combination with Ni: above a critical concentration the Ll2 γ’ phase based on Ni3Al precipitates out of the γ Ni-base solution. However, superalloys usually contain many other alloying elements such as Cr, Co, Mo, W and Ta to enhance strength and impart higher temperature performance. Among these alloying additions, much attention has recently been paid to Re because of its contribution to the improvement of both creep and corrosion properties.

Type
Atom Location by Channeling Enhancement of X-Ray and EELS Signals (ALCHEMI)(organized by J.Spence)
Copyright
Copyright © Microscopy Society of America 2001

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References

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