Ultra-High-Damping Metal Matrix Composites Based On Powders of Shape Memory Alloys

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Now a day, high damping materials have attracted the scientific and technological interest, because of their useful applications. Indeed, the use of high damping materials may allow to decrease the acoustic pollution, improve the speed and precision of the tools machines, increase the life of the aeronautical components and to protect buildings against earthquake, for instance.

In our laboratory, we have developed a new kind of metal matrix composites, specifically designed to exhibit an ultra-high-damping behavior. These composites are based on a high percentage pre-form of powders of Cu-Al-Ni shape memory alloys (SMA), infiltrated by a soft metallic matrix. The damping properties have been measured by mechanical spectroscopy between 150 K and 400 K as a function of temperature and frequency. Finally, we discuss the observed damping behavior and the possible interpretation, taking into account the microstructure of the material, which has been characterized in parallel.

The obtained results are very promising, because the material exhibits, in some range of temperature, an internal friction as high as 0.6, with a merit index higher than other materials considered for structural damping. This way, the developed materials exhibit great interest for damping applications, as for instance seismic protection. Finally we should comment that these composites have been world-wide patented and are ready for prototype development.