T. C. P. phase particles embedded in a superalloy matrix: Interpretation and prediction of the orientation relationships. [Topologically close packed]
- ONERA, Chatillon (France). de la Division Leclerc
- CNRS-ONERA, Chatillon (France)
The compositions of Ni-based superalloys designed for high temperature applications exhibit large contents of refractory elements such as Mo, W or Re. Besides their beneficial influence on the high temperature properties, these elements may promote the precipitation of numerous embrittling phases. The major ones are T.C.P. (Topologically Close Packed) phases and carbides. The alloy of interest in this paper is the MC2 single crystal superalloy, designed for the manufacture of aeronautical engine turbine blades (composition (wt. %): Ni-5Co-8Cr-2Mo-8W-5Al-1.5Ti-6Ta). The [gamma] austenitic matrix is reinforced by a high fraction of ordered [gamma][prime] precipitates (Ni[sub 3](Al,Ti,Ta)). The very high creep resistance of MC2 superalloy, especially at high temperature (exceeding 1,000 C), is due, notably, to a critical high amount of Mo and W refractory elements which, in return, renders the alloy prone to T.C.P. phase precipitation. In the MC2 alloy, the T.C.P. phase growing preferably is a [mu]-type phase. According to microprobe analysis, this [mu] phase has the following composition (wt. %): 16.9Ni-9.5Cr-4.2Co-11Mo-53.5W-0.1Al-0.5Ti-4.3Ta. In spite of its intrinsic brittleness, the [mu] phase has been found to have no detrimental effect on the MC2 mechanical properties. Microstructural observations reveal that the [mu] phase particles exhibit different shapes, which is usually indicative of several types of Orientation Relationships (O.R.) between the particles and the matrix. This study aims at identifying these O.R. and at interpreting their multiplicity with the help of the icosahedron geometrical features.
- OSTI ID:
- 7114952
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Vol. 30:12; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM ALLOYS
MICROSTRUCTURE
CHROMIUM ALLOYS
COBALT ALLOYS
MOLYBDENUM ALLOYS
NICKEL BASE ALLOYS
TANTALUM ALLOYS
TITANIUM ALLOYS
TUNGSTEN ALLOYS
EXPERIMENTAL DATA
GRAIN ORIENTATION
HEAT RESISTING ALLOYS
PHASE STUDIES
ALLOYS
DATA
HEAT RESISTANT MATERIALS
INFORMATION
MATERIALS
NICKEL ALLOYS
NUMERICAL DATA
ORIENTATION
360102* - Metals & Alloys- Structure & Phase Studies