The thermal stability of intermetallic compounds in an as-cast SX co-base superalloy

Lopez-Galilea I, Zenk C, Neumeier S, Huth S, Theisen W, Göken M (2015)

Publication Status: Published

Publication Type: Journal article

Publication year: 2015

Journal

Advanced Engineering Materials Wiley

Book Volume: 17

Pages Range: 741-747

Journal Issue: 6

DOI: 10.1002/adem.201400249

Abstract

The nature and stability of intermetallic phases in a multi-component γ/γ′ Co-base superalloy is investigated. At least three kinds of unwanted intermetallic phases form due to the segregation of Al, Ta, Ti, Si, and Hf during casting in the interdendritic areas in addition to γ and γ′. One of the intermetallic phases that shows a blocky shape, contains high content of Ta, Hf, and Ti and has been identified as a topologically close-packed Laves phase. A B2 phase appears as relatively big pools and in some cases contains needle-shaped precipitates with high content of Al and Ti. The thermal stability of these intermetallic phases is studied in this work under defined heat treatments. The needle-shaped precipitates already dissolve at 1000°C, whereas the B2 phase is dissolved only at higher temperatures of 1200°C. Small amounts of Laves phases remained stable during aging at 1200°C for 25h. The prediction of phases as well as their stability is also checked by the CALPHAD method. The TCNi5 database, containing the description of Co3(Al,W), predicts the presence of the observed intermetallic phases; however, the predicted main transformation temperatures for these phases differ from the experimentally obtained values. This work studies the nature and stability of three intermetallic phases - Laves, B2 and needle-shaped precipitates - in a multi-component γ/γ′ Co-base superalloy, named ERBO-Co0. These phases are generated during casting at the interdendritic areas. Experimental characterization of intermetallic phases is contrasted with thermodynamic calculations, which predicts the presence of the identified phases.

Authors with CRIS profile

Christopher Zenk Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Steffen Neumeier Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Mathias Göken Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Additional Organisation(s)

Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Related research project(s)

Single crystal y/y'-hardened Co-base superalloys - alloy development, heat treatment strategies and mechanical properties (B03) (SFB/TRR 103) SFB/TRR 103: Vom Atom zur Turbinenschaufel - wissenschaftliche Grundlagen für eine neue Generation einkristalliner Superlegierungen Jan. 1, 2012 - Dec. 31, 2015

Involved external institutions

Ruhr-Universität Bochum (RUB) DE Germany (DE)

How to cite

APA:

Lopez-Galilea, I., Zenk, C., Neumeier, S., Huth, S., Theisen, W., & Göken, M. (2015). The thermal stability of intermetallic compounds in an as-cast SX co-base superalloy. Advanced Engineering Materials, 17(6), 741-747. https://doi.org/10.1002/adem.201400249

MLA:

Lopez-Galilea, Inmaculada, et al. "The thermal stability of intermetallic compounds in an as-cast SX co-base superalloy." Advanced Engineering Materials 17.6 (2015): 741-747.

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