Investigation of the dynamic Young's modulus and vibration damping for cryomilled NiAl-AlN composites

Measurements were made of the dynamic Young's modulus (stiffness) and damping for NiAl specimens containing varying amounts of aluminium nitride and prepared by cryomilling. Five specimens of NiAl–AlN were measured at room temperature, each specimen having a different percentage of AlN in the range 1%–30%. Further measurements were made on the 1% and 30% AlN specimens for the temperature range 22–495°C. At room temperature, the Young's modulus of the NiAl–AlN specimens decreased linearly with increasing percentage of AlN. The temperature dependence of Young's modulus for the 1% and 30% AlN specimens was found to be linear. These results were compared with those of typical nickel-based superalloys for a similar temperature range. The damping for all of the NiAl–AlN specimens was of the order of that for other intermetallic compounds (10-3–10-4). The study opened up the possibility of NiAl–AlN being a less-expensive and more easily produced alternative to nickel-based superalloys for high-temperature, high-stiffness applications. © 1998 Kluwer Academic Publishers