1015 強磁性形状記憶合金NiMnGa/ポリマーコンポジットの作製と評価(S03-3 形状記憶合金の特性と応用技術(3),21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

抄録

Ferromagnetic shape memory alloys (FSMAs) can have larger strain and more quick response than presently-used actuator materials. In FSMAs, the magnetic field-induced strains (MFISs) result from rearrangement of martensitic variants by magnetic field. Several research groups have reported large MFISs〜10% in some nonstoichiometric NiMnGa "single crystals". However, they are essentially irrecoverable upon removal of the field. In our laboratory, NiMnGa/polymer composites are proposed for recoverable MFISs. Polycrystalline NiMnGa was crushed into particles and they were embedded in a polymer matrix. The particles are essentially single crystals. In the present study, rearrangement of twin variants under externally applied fields were observed in embedded particles.