Damping behavior of polymer composites with high volume fraction of NiMnGa powders

Comparison of magnetic field controlled damping properties of single crystal Ni-Mn-Ga and Ni-Mn-Ga polymer hybrid composite structures

“…The measured values of tan δ are comparable to those reported previously [8,4,11] for Ni-Mn-Ga -polyurethane and -epoxy composites, despite that the pure Hysol 9455 epoxy has a higher tan δ (Fig. 3d) than the Lord polyurethane [4] or the Bisphenol-a-epoxy [11]. When the current results are compared with melt-spun Ni-Mn-Ga composites [16], the measured tan δ is higher in the Tg to Af (austenite finish) temperature range, however, at a higher temperature the tan δ of the melt spun composite is higher.…”

“…3f). The measured values of tan δ are comparable to those reported previously [8,4,11] for Ni-Mn-Ga -polyurethane and -epoxy composites, despite that the pure Hysol 9455 epoxy has a higher tan δ (Fig. 3d) than the Lord polyurethane [4] or the Bisphenol-a-epoxy [11].…”

“…This has been confirmed in [10] where a composites with filling ratio between 30-40 vol.% displayed enhanced damping capability. However, at higher volume fractions the epoxy composites may become prone to cracking [11,12].…”

“…So far, the costs and the difficulties related to manufacturing of Ni-Mn-Ga single crystals and the brittle nature of the material [4] have hindered its widespread use. As a viable alternative to bulk single crystals, magnetic shape memory (MSM)-hybrid composite structures have been proposed [5][6][7][8][9][10][11][12][13][14][15][16].…”

“…Previously, such Ni-Mn-Ga composite structures have been produced from particulates manufactured either by crushing [7][8][9][10][11][12][13][14] or cutting [15] of single crystals or from specialized processes such as spark erosion [9] or melt-spinning [16]. However, these do not solve the complexity related to single crystal manufacturing.…”