LPBF-Titan: Researchers embed functional strain sensors into metal
Self-monitoring metal components are getting closer. A research team has embedded functioning multi-layer strain sensors directly into titanium, which is produced in laser Powder Bed Fusion (LPBF). So far, such an endeavor has mostly failed due to heat. Polymers dielectric materials and adhesives carbonize or detach at high temperatures. Therefore, earlier attempts often used stainless steels or nickel alloys and relied on cavities, coatings, or retrofitted components. Titanium, especially Ti-6Al-4V, further complicates the project due to its low thermal conductivity and narrow process window. Especially in aerospace and implants, integrated sensor technology would be particularly useful. A team from Argonne National Laboratory, University College London, and the University of Sheffield combines several approaches. They write conductive tracks via Direct Ink Writing (DIW), use a tailored polymer dielectric, and apply a powder-based thermal barrier before melting the top layer. The dielectric consists of a thin layer of tripropylenglycol diacrylate (TPGDA), followed by DIW tracks made from a silver nanoparticle ink. Surface optimization via low-current plasma enabled structure widths of around ten micrometers. Above approximately 200 degrees Celsius, the polymer degradation accelerates. Curing at 150 degrees for over 3,800 seconds provided stable resistance of around 350 ohms.
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