Precipitation in Iron Aluminides Containing Carbon and Titanium, Zirconium or Niobium
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Cornelia Schlesier
Abstract
Three iron aluminide alloys with the composition Fe-40Al- 0.5X-0.2C-0.05B, in at.% (X = Ti, Zr, Nb), have been investigated by means of optical, scanning and transmission electron microscopy. All three alloys were extruded and exhibited small grain sizes ranging from 12 to 40 μm. The precipitate volume fractions and lattice parameters were consistent with the low predicted solubilities in these alloys. While the Ti- and Nb-containing alloys formed, as expected, TiC and NbC precipitates, the Zr-containing alloy contained a ternary intermetallic phase (Fe6Al6Zr). In addition, an unidentified Fe–Al–Zr phase with a Zr concentration of approximately 23 at.% as well as ZrC were found. The precipitate morphologies were also very different in the three alloys. Whereas in the Ti-containing alloy the TiC phase tended to occur in the form of needles, the precipitates were more equiaxed in the Zr-containing alloy. The NbC particles were also equiaxed and occurred either as isolated particles in the interior of the grains or as clusters at the grain boundaries.
Abstract
Drei Eisenaluminid-Legierungen der Zusammensetzung Fe-40Al-0.5X-0.2C-0.05B, alle Konzentrationsangaben in At.-% (X = Ti, Zr, Nb) wurden mittels optischer, Rasterelektronen- und Transmissionselektronenmikroskopie untersucht. Alle drei Legierungen waren stranggepreβt und hatten Korngröβen zwischen 12 und 40 μm.Der ausgeschiedene Volumenbruchteil und der Gitterparameter stimmen mit der Vorhersage der niedrigen Löslichkeit überein. Während die Ti- und Nb-haltigen Legierungen, wie erwartet, TiC und NbC bilden, enthölt die Zr-haltige Legierung eine intermetallische Phase (Fe6Al6Zr). Zusötzlich wurden noch eine nicht identifizierte Fe – Al – Zr-Phase mit einem Zr-Gehalt von ungeföhr 23 At.% und ZrC-Ausscheidungen gefunden. Während die TiC-Ausscheidungen nadelförmig sind, haben die Fe – Al – Zr-Ausscheidungen eine annähernd sphörische Form. Die NbC-Ausscheidungen sind ebenfalls annähernd sphärisch und sind innerhalb der Körner und in Clustern an den Korngrenzen zu finden.
Funding statement: This research was sponsored by the Division of Materials Sciences, U.S. Department of Energy under contract number DE-AC05-960R22464 with Lockheed Martin Energy Research Corporation. J.H.S acknowledges an invitation by Prof. Wahi to Berlin to participate in this work. The authors are thankful to Drs D. Mukherji, G. Schumacher and C.G. McKamey for the critical reading of the manuscript.
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© 1997 Carl Hanser Verlag, München
Articles in the same Issue
- Frontmatter
- Aufsätze
- Automatic Determination of Dendritic Arm Spacing in Directionally Solidified Matters
- Microstructure and Mechanical Properties of Titanium Castings
- Microstructural Features Controlling the Dry Sliding Wear Response of Some Bearing Alloys
- Correlation of Microstructure and Giant Magnetoresistance in Electrodeposited Ni – Cu/Cu Multilayers
- Microstructure-related Modelling of the Deformation Behaviour of the Superalloy CoCr22Ni22W14
- An Assessment of the Si Mobility and the Application to Phase Transformations in Silicon Steels
- Simulated Weld HAZ of Vanadium Modified 2.25Cr-1Mo Steel
- The Metastable Miscibility Gap in the System Fe–Cu
- Precipitation in Iron Aluminides Containing Carbon and Titanium, Zirconium or Niobium
- Use of a Single Zirconia Electrolyte Cell to Measure Basicity in Binary and Ternary Carbonate Melts
- Adsorption Studies of Water on Copper, Nickel, and Iron: Assessment of the Polarization Model
- Mitteilungen der Deutschen Gesellschaft für Materialkunde e.V
- Personen
- Terminkalender
Articles in the same Issue
- Frontmatter
- Aufsätze
- Automatic Determination of Dendritic Arm Spacing in Directionally Solidified Matters
- Microstructure and Mechanical Properties of Titanium Castings
- Microstructural Features Controlling the Dry Sliding Wear Response of Some Bearing Alloys
- Correlation of Microstructure and Giant Magnetoresistance in Electrodeposited Ni – Cu/Cu Multilayers
- Microstructure-related Modelling of the Deformation Behaviour of the Superalloy CoCr22Ni22W14
- An Assessment of the Si Mobility and the Application to Phase Transformations in Silicon Steels
- Simulated Weld HAZ of Vanadium Modified 2.25Cr-1Mo Steel
- The Metastable Miscibility Gap in the System Fe–Cu
- Precipitation in Iron Aluminides Containing Carbon and Titanium, Zirconium or Niobium
- Use of a Single Zirconia Electrolyte Cell to Measure Basicity in Binary and Ternary Carbonate Melts
- Adsorption Studies of Water on Copper, Nickel, and Iron: Assessment of the Polarization Model
- Mitteilungen der Deutschen Gesellschaft für Materialkunde e.V
- Personen
- Terminkalender
