Nanocrystals reveal damaged material

Predicting material fatigue

Picture of zinc oxide tetrapods taken by scanning electron microscope - Copyright 2012, Wiley
Picture of zinc oxide tetrapods taken by scanning electron microscope - Copyright 2012, Wiley

29.11.2012,  Research news

A small crack in a metal wheel caused Germany’s worst-ever rail accident – the 1998 Eschede train disaster. The problem: it was practically impossible to detect damage of that nature to a metal by inspecting it externally. But now scientists have succeeded in making material fatigue visible. They designed new synthetic materials that emit light to report high mechanical stress.

Researchers from the Technische Universität München (TUM), Christian-Albrechts-Universität zu Kiel (CAU) and Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) developed this new technology for composite materials. These light yet robust materials are able to withstand considerable mechanical loads. They are typically used in cars and medical equipment. 

“For our experiments we mixed silicone with special zinc oxide crystals called tetrapods,” explains Professor Cordt Zollfrank of TUM. “The composite material is more stable and reveals a visible change in the intensity and color components of its reflected light under stress.”

So the material sends out a signal to report excessive mechanical stress, allowing maintenance personnel to replace the component to prevent an accident. The research team is convinced that its discovery will open up new avenues for the design of innovative composite materials. According to Prof. Zollfrank: “We expect further exciting developments in the area of these self-reporting materials.”

Media photos for download:

Picture of zinc oxide tetrapods taken by scanning electron microscope - Copyright 2012, Wiley; reproduced with permission (DOI:10.1002/adma.201203849)
Picture of zinc oxide tetrapods taken by scanning electron microscope - Copyright 2012, Wiley; reproduced with permission (DOI:10.1002/adma.201203849)
The experimental setup shows how the composite material was stretched and exposed to light. At the same time, the reflecting light was measured. Copyright 2012, Wiley; reproduced with permission (DOI:10.1002/adma.201203849)
The experimental setup shows how the composite material was stretched and exposed to light. At the same time, the reflecting light was measured. Copyright 2012, Wiley; reproduced with permission (DOI:10.1002/adma.201203849)

More Information
Self-reporting-materials_EN.pdf(146 Kbyte)


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