Magnetic-field-induced bending and straining of Ni–Mn–Ga single crystal beams with high aspect ratios
Magnetic-field-induced bending and straining of Ni–Mn–Ga single crystal beams with high aspect ratios
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DOI：
10.1016/j.actamat.2015.05.030
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发表时间：
2015-08
期刊：
影响因子：
9.4
通讯作者：
Nikole J. Kucza;C. Patrick;D. Dunand;P. Müllner
中科院分区：
文献类型：
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作者：
Nikole J. Kucza;C. Patrick;D. Dunand;P. Müllner
磁性形状记忆合金(MSMA)Ni-Mn-Ga单晶束的横截面为1×1 mm，长度在2~10 mm之间，具有10M马氏体结构，所有面平行于{100}，在旋转磁场中一端保持。通过磁场诱导应变(MFIS)和磁扭矩诱导弯曲(MTIB)，梁分别沿平行和垂直于梁纵轴的方向变形。当电场平行于光束轴时，光束是直的和短的。在磁场旋转时，光束向着磁场的方向拉长和弯曲。当电场达到90°时，光束迅速偏转，呈相反方向的弯曲形状。随着磁场的进一步旋转，弯曲应变和轴向应变逐渐减小，直到在180°的电场作用下，梁又变短变直。随着梁高宽比的增大，弯曲分量增加，而总轴向应变保持不变。MTIB是暴露在横向磁场中的长MSMA样品的一种自然但迄今被忽视的响应，它发生在电流线性(一维)执行器的切换过程中，从而导致摩擦损失、磨损和疲劳。然而，MTIB提供了在所有方向(三维)连续且平滑地驱动高深宽比MSMA的机会，从而模仿细长的生物驱动结构，如鱼的微生物鞭毛尾巴和鳍、心脏瓣膜、植物的叶子和花瓣以及鸟类或昆虫的翅膀。
Small monocrystalline beams of the magnetic shape-memory alloy (MSMA) Ni–Mn–Ga, with a square 1×1 mm2cross 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 field – occurs 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.