A rapid FIB-notch technique for characterizing the internal morphology of high-performance fibers

• A new sample preparation technique for high-performance fibers is presented.
• Focused ion beam is used mill notches in single high-performance fibers.
• Subsequent atomic force microscopy generates modulus maps of fiber interior.
• Method applied to single Kevlar KM2 fiber and brief structural analysis provided.
• Method used successfully on other fiber systems showing technique's flexibility.

This work introduces an innovative technique to characterize the internal morphology of high-performance fibers by using a focused ion beam (FIB) sample preparation method and subsequent atomic force microscopy (AFM). A FIB is used to mill opposing notches that facilitate direct failure along a longitudinal shear plane, and expose the internal surface of the fiber. By exposing this surface via longitudinal shear, distortion of the cleaved surface is minimal, which is an advantage over surface preparation methods such as microtoming. After cleaving the notched fibers, an AFM technique is used to generate modulus maps of the fiber fracture surfaces. These modulus maps provide qualitative and quantitative microstructural information. Initial results obtained from Kevlar KM2 and Dyneema SK76 fibers are presented and a brief analysis of the observed internal features is provided. Extending the technique to image internal features in other materials is also discussed.