Characterizing Heat Effects from Femtosecond Laser Cutting of Nitinol Tubes

Femtosecond laser cutting is largely marketed as an athermal cutting process for the manufacture of Nitinol devices. The extreme thermal-sensitivity of Nitinol’s microstructure and thermomechanical performance makes low heat input secondary processes a necessity. The true athermal nature of the femtosecond laser cutting process however, has not yet been investigated in great depth. In this work the process – microstructure – performance relationship is identified through studying the femtosecond laser cutting of a 0.006” (150 µm) wall Nitinol tube, utilizing a single pass strategy. The heat affected region adjacent to the laser cut wall is characterized via microscopy as well as through nanoindentation techniques. Nanoindentation mapping of laser cut strut cross-sections provides excellent visualization into thermal damage profiles and insight into how the process must be optimized to limit the effects on device performance.