Magnetic Shape Memory Alloy Ni50-Mn28-Ga22 MSMA Magnetostrcitive Material

The Magnetic Shape Memory (MSM) eàect in a Ni-Mn-Ga alloy was discovered in 1996 at MIT by Dr. Kari Ullakko and co-workers
The first MSM alloy showed a strain of 0.2%. Since then, huge improvements have been achieved in the production process
of MSM alloys as well as in the post-production treatments and training.

MSM alloys are ferromagnetic materials that produce motion and force under moderate magnetic fields (typically higher than 0.2 T). They are single crystalline alloys of Nickel, Manganese and Gallium and are able to produce 6% strain under more than 2 MPa external load (see Fig. 3). Frequencies up to lower kilohertz range can be achieved.

The main properties of commercially available Ni50-Mn28-Ga22 alloys are:

• Typical strain up to 6%
• Blocking stress up to 3.5 MPa
• Magnetic Õeld for maximum strain of about 500 kA/m
• Full strain up to about 2 MPa load
• Work output per unit volume of about 150 kJ/m³
• Energetic eÞciency up to 90%
• Reaction times of about 1 ms (in MSM actuators)
• Hysteresis between stress or magnetic Õeld and strain (material damping)
• Internal friction
• Magnetic and thermal activation are both possible
• Operating temperatures: -40 °C to 60 °C
• Change in magnetic permeability and electric resistivity during deformation