Ferromagnetic Shape Memory Alloys

CIMS' main focus in the SMA area is the development of fast responsive Ferromagnetic SMA's with an emphasis on polycrystalline FePd system. The actuation mechanism that we use is "hybrid mechanism", which is a combination of applied magnetic field, and its gradient, magnetic force, stress-induced martensite transformation (SIM), stiffness change from stiff (austenite) to soft (martensite). Polycrystalline FePd based actuators have strong force capability, while inducing reasonably large strain by SIM, yet the material can be shaped into any three-dimensional shape as this is ductile alloy, thus it can sustain high tensile, compressive and shear stress. The strain induced is reversible upon on and off the applied magnetic field (and its gradient).

1. Ferromagnetic SMA (FSMA): background
2. Possible magnetic field driving mechanisms for FSMA actuators
3. Comparisons of magnetic field driving mechanisms
4. Hybrid Mechanism and Demonstration
5. Material characterizations of polycrystalline FePd
6. Advantage of FePd: Shaping into various shapes
7. FePd (thin) spring actuator
8. Compliant Surface Robot