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Title:Investigation of lattice mismatch in rhenium containing nickel-base superalloys
Author(s):Lahrman, David Frank
Department / Program:Metallurgy and Mining Engineering
Discipline:Metallurgical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Lattice Mismatch
Nickel-base Superalloys
Abstract:In this study, three techniques for measuring gamma/gamma prime lattice mismatch were examined on two alloys, each of which had two different ageing heat treatments, i.e. standard age and overaged. Each alloy contained a different Re content so that the effect of this element on lattice mismatch also could be investigated. The techniques used for measuring lattice mismatch were x-ray diffraction, convergent beam electron diffraction and interface dislocation analysis. Additionally, the electron microprobe was used to examine bulk homogeneity and a scanning transmission electron microscope equipped with a Kevex X-ray EDS system was used to examine phase compositions. From this study it was determined that the x-ray diffraction data and the CBED data yield the same results for room temperature lattice mismatch, although CBED requires a significant amount of data in order to be useful due to the scatter in the technique. The dislocation analysis technique gave larger negative values of mismatch. It is believed that these latter values represent those which exist at the aging temperature (1079°C). No effect of Re on lattice mismatch was observed, possibly due to the fact that the lower Re alloy contained more W.
Issue Date:1986
Citation Info:Copyright David F. Lahrman, 1982
Genre:Dissertation / Thesis
Date Available in IDEALS:2015-10-08

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