Investigation of lattice mismatch in rhenium containing nickel-base superalloys

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Metallurgical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Lahrman, David Frank

• Lattice Mismatch
• Alloys
• Nickel-base Superalloys

Language dc:language

en

Identifier

Copyright David F. Lahrman, 1982

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/88334