Non-Destructive Methods for Nitinol Microstructure Characterization

The further development of nanoscale X-Ray microscopy opens opportunitiesfor non-destructive high-resolution 3D microstructure analysis of materials such as Nitinol. In the past, nanoscale 3D X-ray imaging was only possible with synchrotron imaging; now X-ray lab instruments are commercially available. X-ray 3D images can not only show qualitative information, but extract volumetric quantitative information such as particle and voids morphology, crack dimensions and their distribution. Even the visualization of the grains morphology in 3D seems possible. This non-destructive method may especially be used for pre- and post-fatigue inspection and could help understand failure mechanisms of Nitinol parts and devices.

In order to investigate the relevance of nanoscale X-ray imaging for Nitinol, tube and wire sections as well as medical device samples are subject to this study. Based on exemplary measurements, the possibilities and limitations of X-ray imaging are evaluated. Furthermore, this new approach is compared to traditional methods with respect to resolution, sample size and extent of the area of interest.