Ni-Mn-Ga is a ferromagnetic shape memory alloy that exhibits large, magnetic-fieldand stress-induced strains via energy dissipating twinning when processed into single crystals. Grain boundaries suppress twinning and render polycrystalline Ni-Mn-Ga brittle.Ni-Mn-Ga/polymer composites overcome the drawbacks of polycrystals and could thus provide a less expensive and easier to handle alternative to Ni-Mn-Ga single crystals for damping applications. Ni-Mn-Ga wires were produced by melt-spinning and were polycrystalline in the as-spun state. Annealed wires were ferromagnetic at room temperature with non-modulated martensite and a bamboo microstructure. The annealed wires displayed a hysteretic stress-strain behavior typical for twinning. Ni-Mn-Ga wire- * Corresponding author. epoxy matrix composites were fabricated with as-spun and annealed wires. The damping behavior of annealed Ni-Mn-Ga wire-epoxy matrix composites was higher than that of asspun Ni-Mn-Ga wire-epoxy matrix composites and of pure epoxy.

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a b s t r a c tSmall monocrystalline beams of the magnetic shape-memory alloy (MSMA) Ni-Mn-Ga, with a square 1Â1 mm 2 cross section and length between 2 and 10 mm, with the 10M martensite structure and all faces parallel to {100}, were subjected to rotating magnetic fields while being held at one end. The beams deform by both magnetic-field-induced straining (MFIS) and magnetic-torque-induced bending (MTIB), in directions parallel and perpendicular to the beam's longitudinal axis, respectively. With the field parallel to the beam axis, the beams were straight and short. Upon field rotation, the beam elongated and bent in the direction of the field. When the field reached 90°, the beam deflected rapidly and took a bent shape oriented in the opposite direction. Upon further field rotation, bending strain and axial strain decreased until the beam was short and straight again with the field at 180°. With an increase in beam aspect ratio, the bending component increases while the total axial strain remains constant. MTIB -a natural but so far neglected response of long MSMA samples exposed to a transversal magnetic fieldoccurs during switching of current linear (one-dimensional) actuators, thus causing friction losses, wear, and fatigue. However, MTIB provides the opportunity to actuate high aspect ratio MSMA continuously and smoothly in all directions (in three dimensions), thus mimicking slender biological actuating structures such as microorganism flagella tails and fins of fish, heart valves, leaves and petals of plants, and wings of birds or insects.

Ferromagnetic Ni-Mn-Ga shape memory alloys with large magnetic field-induced strains are promising candidates for actuators. Here, we cast replicated Ni-Mn-Ga foams with 57 vol.% of 355-500 m open pores, with and without directional solidification. The 10M martensitic phase was determined in all foam samples. Directionally solidified foam had a fiber texture with <100> closely aligned with the solidification direction. In contrast, foams without directional solidification were more randomly textured. One directionally solidified foam showed a maximum magnetic-field induced strain of 0.65%, which was twice the value displayed by other foams without directional solidification. This improvement is consistent with a reduction in incompatibility stresses between neighboring grains deforming by twinning, generated by a reduction in crystallographic misorientation in textured foam.