Shape Memory Alloys (SMA)

Intro

Shape-Memory Alloys are materials which can be deformed at lower temperatures but return to their original shape after being heated.

(Works, 2025)

The most common type of shape memory alloy is nickel-titanium, which is also known as Nitinol. Other types are usually copper or iron based which sometimes have better, more specific use cases.

(Works, 2025)

Shape memory alloys have been adopted in aerospace, automotive, robotics, and biomedical engineering due to their unique & functional behaviour.

(Rodinò and Maletta, 2024)

Case Study — Eyeglass Frames — Flexon® (Marchon Eyewear)

(Flexon Glasses | Flexible Memory Metal Titanium Frames, no date)

Flexon glasses uses Nitinol wire cores, which can bend and twist without breaking, and then return to their original shape when heated.

It is a perfect example how SMA's can be used in a every day scenario. It demonstrates durability, user comfort and design longevity through super-elasticity.

Smart Memory Alloys can replace or even out-perform traditional hinges or spring mechanisms due to material intelligence, not mechanical complexity.

Manufacturing and the Future of SMA's

Traditionally, SMA's are usually melted, hot worked and extruded into wire, rods or sheets. While these process work well on scale, they limit geometric complexity and restrict design integrations.

(Rodinò and Maletta, 2024)

Recent research on additive manufacturing as an alternative route for making SMA's shows that complex geometry can be produced while retaining that functional shape memory behaviour. The particular additive manufacturing technique is laser powder bed fusion (LPBF).

(Rodinò and Maletta, 2024)

Image: (Ntebogeng Mogale, Matizamhuka and Cobbinah, 2021)

Loosely similar to how a commercial resin 3D printer works, Laser power bed fusion uses a laser which precisely melts metal powder that lies in a bed, after each layer the powders height is increased and the lasering process repeats.

(Ntebogeng Mogale, Matizamhuka and Cobbinah, 2021)

Conclusion

Instead of being limited to wires or simple forms, SMAs can be well integrated into designs without adding mechanical assemblies.

This opens opportunities to reduce part count, simplify products, and embed responsive behaviour directly into form.

While this emerging process will create many great product opportunities, its important to factor that due to cost and specialised processing, SMAs are best suited to high-value or performance-critical applications rather than mass-market products.

References

Works, H.E. (2025) What are shape memory alloys, and how do they work?, How Engineering Works. Available at: https://www.howengineeringworks.com/questions/what-are-shape-memory-alloys-and-how-do-they-work-2/.

Rodinò, S. and Maletta, C. (2024). Design considerations and applications of shape memory alloy-based actuation in morphing structures: A systematic review. Progress in Engineering Science, [online] 1(4), p.100021. doi:https://doi.org/10.1016/j.pes.2024.100021.

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Flexon Glasses | Flexible Memory Metal Titanium Frames (no date) www.flexon.com. Available at: https://www.flexon.com/.

Ntebogeng Mogale, Matizamhuka, W. and Cobbinah, P. (2021). Hot Corrosion and Oxidation Behaviour of TiAl Alloys during Fabrication by Laser Powder Bed Additive Manufacturing Process. IntechOpen eBooks. doi:https://doi.org/10.5772/intechopen.100345.

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