Creep of particle-reinforced NiAl intermetallics: New materials for up to 1400 {degree}C
- Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)
The intermetallic compound NiAl is a promising high temperature material as it possesses a favorable combination of advantageous properties (high melting point, low density, high thermal conductivity, good oxidation resistance). However its creep resistance is far inferior to that of advanced superalloys. The authors have developed new powder-metallurgical NiAl alloys, where the creep strength is raised by incorporating fine yttria dispersoids. The materials are produced by mechanical alloying and subsequent coarse-grain recrystallization at temperatures close to the solidus temperature. The resulting alloys show exceptional creep strength up to 1,400 C, thereby exceeding the temperature capability of superalloys significantly. The creep properties are in agreement with their recently developed model for ``detachment-controlled creep``, in which the release of dislocations from incoherent particles determines the creep rate. In addition, the brittleness problem at room temperature can be moderately alleviated by incorporating coarse ductile phases such as Mo. While the particles raise the critical stress intensity factor, they do not improve the room temperature tensile ductility.
- OSTI ID:
- 78370
- Report Number(s):
- CONF-941144--; ISBN 1-55899-265-0
- Country of Publication:
- United States
- Language:
- English
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