Internal friction and dynamic Young's modulus of aluminium composites reinforced in situ with TiB2 and Al2O3 particulates

Aluminium based metal matrix composites (MMCs) reinforced in situ with TiB2 and Al2O3 particulates were fabricated via the exothermic reaction of TiO2, Al and B powders in the Al-TiO2-B system. The interfaces between in situ Al2O3 and TiB2 particulates and the aluminium matrix were clean and free from interfacial phase. The internal friction behaviour of such novel composites over a temperature range of 30-500degreesC was investigated using a dynamic mechanical analyser. The results showed that the Al2O3 and TiB2 particulates enhance the dynamic Young's modulus of Al significantly. Moreover, the in situ TiB2 and Al2O3 particulates also improve the damping capacity of Al. The damping capacity of the MMCs was found to increase with increasing temperature. The correlation between the damping capacity of MMCs with the microstructure is discussed.