Investigations of the Crystallographic Orientation on the Martensite Variant Reorientation of the Single-Crystal Ni-Mn-Ga Cube and Its Composites for Actuator Applications

High-speed actuators are greatly required in this decade due to the fast development of future technologies, such as Internet-of-Things (IoT) and robots. The ferromagnetic shape memory alloys (FSMAs), whose change could be driven by applying an external magnetic field, possess a rapid response. Hence, these materials considered promising candidates for applications technologies. Among FSMAs, Ni-Mn-Ga-based were chosen their large deformation strain appropriate phase transformation temperatures near-room temperature applications. Nevertheless, it is widely known that both intrinsic brittleness Ni-Mn-Ga alloy constraint existence grain boundaries polycrystal inhibit Therefore, various composite designed study, behaviors induced compressive or fields examined situ micro CT observations. In addition, dependence martensite variant reorientation (MVR) on crystallographic directions was also investigated. It found most MVRs active within field range applied regime <100>p, <110>p, <111>p single-crystal {100}p cubes.