3D-printed magnetostrictive steel sensors open up new possibilities for smart applications

Additive manufacturing is becoming increasingly important for functional materials that go beyond purely structural tasks. A recent research project at the University of Sheffield demonstrates how magnetostrictive materials can be specifically tailored for sensor and actuator applications using 3D printing. This is particularly relevant for fields such as structural health monitoring, the Internet of Things, and medical metrology, where compact and easily integrable sensor concepts are required.

The study focused on the use of an extrusion-based system that works with a polymer-bonded metal feedstock. Initially, so-called green parts are produced, which are then debound and sintered to create dense metal components with more than 99 percent of theoretical density. This approach avoids high process temperatures during printing and enables precise realization of complex geometries. Stainless steel 17-4 PH was used as the material, as it is suitable as a soft-magnetic material for smart systems due to its low coercive field strength and high saturation magnetization.

Among other things, honeycomb-like structures with varying strut widths were printed to investigate the influence of geometry on magnetic properties. Characterization was carried out using a SQUID magnetometer across several process stages, from the raw material through printing to the sintered component. The results showed that coercivity in the final state decreased by 12.6 percent, while saturation magnetization increased by around 18 percent. At the same time, magnetic anisotropy was reduced, which is attributed to grain growth and reduced porosity after sintering.

“This project has been invaluable to my PhD degree. I would like to thank the Royce Translational Centre and the University of Sheffield for bringing this project together as I have learnt so much from them,” said Nisar Ahmed, Doctoral Researcher.