Acoustic energy absorption in Ni–Mn–Ga/polymer composites

Abstract

Composites of Ni–Mn–Ga particles in a polyurethane (PU) matrix are known to show up to 70% energy absorption under quasi-static mechanical loading. Reported here are results showing that the large mechanical energy absorption in Ni–Mn–Ga/PU composites persists up to at least 1 kHz and exceeds that in each of these control samples of pure PU, as well as in Fe 2(Tb 1/3Dy 2/3) particles in epoxy, and single crystal Ni–Mn–Ga. The transmitted acoustic amplitude decreases linearly with increase in frequency, consistent with the theory, and at 1 kHz it is 0.7 V in the Ni–Mn–Ga single crystal, 0.65 V in pure PU, 0.45 in the Fe 2(Tb 1/3Dy 2/3)/PU composites and 0.25 V in Ni–Mn–Ga/PU composites.