FGL-Aktorik – EN
Actuators – High-Tech with a Memory
Shape memory alloys (SMA) have been revolutionizing industries from aerospace and automotive to consumer electronics for decades.
What is behind it?
The special effect of SMA is based on a thermally or mechanically induced phase transformation. This results in, among other things:
- Pseudoelasticity: "Elastic" behavior up to 8% strain
- Pseudoplasticity: Stress-strain behavior usable for actuation
- Internal sensor effect: Resistance change during phase transitions
Material Basics
- Nickel-titanium alloys (binary/ternary)
- Available as wire, rod, tube, or sheet
- Transformation temperature: -200 °C to +100 °C
- Strain: up to 5% (depending on cycle count)
- Blocking forces: up to 400 N/mm²
- Cycle stability: up to >3 million cycles
- Extremely high specific energy density → ideal for miniaturization
The Discovery of the Effect
As early as 1959, William J. Buehler discovered the first unique properties of NiTi alloys. Since then, progress has been rapid:
- 1961: Shape memory effect discovered by chance
- 1962: First description by F. E. Wang
- 1967: First conference on SMA technology
Applications in Industry & Everyday Life
First mass production applications
- 1969: 200 bar connector for Grumman F-14 (Cryofit)
- 2004: First SMA wire application: "Omnipod" insulin pump
Consumer
- 1988: Philips Café Gourmet – SMA valve controls water flow
- Later: Rice cookers, air conditioning units, thermal valves
Automotive
- 1989: Mercedes S-Class – SMA bypass valve for power steering
- 2005: CVT oil level control (Mercedes A/B Class)
- Today: Battery thermal management, cooling air, oil
Consumer Electronics
- 2015: Smartphone cameras – autofocus & image stabilization with SMA wire
- 2023: SMA 8-Wire System – combination of AF and OIS (40 million units)
