English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  The role of local chemical composition for TCP phase precipitation in Ni-base and Co-base superalloys

Hammerschmidt, T., Koßmann, J., Zenk, C. H., Neumeier, S., Göken, M., Lopez-Galilea, I., et al. (2016). The role of local chemical composition for TCP phase precipitation in Ni-base and Co-base superalloys. In Proceedings of the International Symposium on Superalloys (pp. 89-96). Pittsburgh, PA, USA: Minerals, Metals and Materials Society.

Item is

Basic

show hide
Item Permalink: http://hdl.handle.net/21.11116/0000-0001-B9CD-8 Version Permalink: http://hdl.handle.net/21.11116/0000-0001-B9D0-3
Genre: Conference Paper

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Hammerschmidt, Thomas1, Author              
Koßmann, Jörg1, Author              
Zenk, Christopher H.2, Author              
Neumeier, Steffen2, Author              
Göken, Mathias2, Author              
Lopez-Galilea, Inmaculada3, Author              
Mújica Roncery, Laís4, Author              
Huth, Stephan3, Author              
Kostka, Aleksander5, 6, Author              
Theisen, Werner3, Author              
Drautz, Ralf7, Author              
Affiliations:
1ICAMS, Ruhr-Universität Bochum, Bochum, Germany, ou_persistent22              
2Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Materials Science and Engineering, Institute i, Martensstr. 5, 91058 Erlangen, Germany, ou_persistent22              
3Lehrstuhl Werkstofftechnik, Ruhr-Universität Bochum, Bochum, Germany, ou_persistent22              
4Lehrstuhl Werkstofftechnik, Ruhr-Universität Bochum, Bochum, Germany, persistent22              
5High-Temperature Materials, External Max Planck Fellow, Max-Planck-Institut für Eisenforschung GmbH, Max Planck Society, ou_1863347              
6Center for Electrochemical Sciences (CES), Ruhr-Universität Bochum, 44801 Bochum, Germany, ou_persistent22              
7ICAMS, Materials Research Department, Ruhr-Universität Bochum, Universitätsstraße 90a, Bochum, Germany, ou_persistent22              

Content

show
hide
Free keywords: Characterization; Chemical analysis; Chemical stability; Crystal microstructure; Crystal structure; Electron microscopy; Electron probe microanalysis; High resolution transmission electron microscopy; Materials handling equipment; Microstructure; Nickel; Precipitation (chemical); Scanning electron microscopy; Single crystals; Solidification; Stability; Structure (composition); Superalloys; Ternary systems; Thermodynamic stability; Titanium; Topology; Transmission electron microscopy; X ray spectroscopy, Co-base superalloys; Intermetallic precipitates; Ni-base superalloys; Structure maps; Topologically close-packed phasis, Transmission control protocol
 Abstract: The precipitation of topologically close-packed (TCP) phases in single-crystal superalloys is highly undesirable due to the detrimental effect on the mechanical properties. The TCP phases bind atoms responsible for the solid solution strengthening of the γ′ phase (Re, W, Mo), as well as elements that are important for the formation of the γ phase (Ti, Ta). A thorough understanding of TCP phase precipitation is therefore a prerequisite for the design of future superalloys. The thermodynamic stability of TCP phases as bulk material is meanwhile well understood. However, little is known about the factors that govern the stability of the experimentally observed precipitates of TCP phases within the superalloy matrix. The focus of this paper is the role of the local chemical composition for the stability of TCP phase precipitates. We combine experimental measurements of the local chemical composition of TCP phase precipitates in the Ni-base superalloy ERBO-1 and the Co-base superalloy ERBO-Co0 with a theoryguided interpretation of the structural stability of bulk TCP phases. The experimental characterization of the microstructure and the crystal structure of the precipitates are based on scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The local chemical composition is determined by energydispersive X-ray spectroscopy (EDX) and electron probe microanalysis (EPMA). The measured local chemical compositions are assessed regarding the likelihood of TCP phase formation by determining their location in a structure map of the stability of bulk TCP phases. This establishes a direct link between the measured local chemical composition of TCP phase precipitates and the phase stability of bulk TCP phases at this composition. By converting the measured local chemical composition into structure-map coordinates, we effectively construct a compound map that indicates the regions in the microstructure that are prone to TCP phase precipitation. Analyzing the intermetallic precipitates in more detail, we find that the chemical compositions of the TCP phase precipitates would be expected to form the same TCP phase as bulk material. This suggests that the observed precipitates of TCP phases can be regarded to be in a local thermodynamic equilibrium. The challenge of predicting TCP phase precipitation in superalloys is hence reduced to the prediction of the local chemical composition during casting, heat treatment and service.

Details

show
hide
Language(s): eng - English
 Dates: 2016
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Method: -
 Identifiers: BibTex Citekey: Hammerschmidt201689
ISBN: 978-111899666-9
 Degree: -

Event

show
hide
Title: 13th International Symposium on Superalloys, SUPERALLOYS 2016; Seven Springs Mountain ResortSeven Springs
Place of Event: Seven Springs, PA, USA
Start-/End Date: 2016-09-11 - 2016-09-15

Legal Case

show

Project information

show

Source 1

show
hide
Title: Proceedings of the International Symposium on Superalloys
Source Genre: Proceedings
 Creator(s):
Affiliations:
Publ. Info: Pittsburgh, PA, USA : Minerals, Metals and Materials Society
Pages: - Volume / Issue: 2016 Sequence Number: - Start / End Page: 89 - 96 Identifier: -