A. Schuessler, M. Strobel, R. Steegmueller, ADMEDES SCHUESSLER GmbH, Pforzheim, Germany
Joining of Nitinol by laser welding offers advantages for designing complex shaped medical components. However, there are concerns regarding the durability and corrosion behaviour of welded components for the use of welded joints in vascular implants. The authors discuss the status of joining NiTi-alloys to itself and to dissimilar materials based on a literature review and own past results. Investigations are performed on tubing and components of a binary superelastic NiTi-alloy. The role of process parameters on the microstructure of the weld, the heat affected zone and the tensile properties of laser welded tubing is discussed. The corrosion behaviour of laser welded Nitinol stents is assessed compared to “unwelded” stents via potentiodynamic polarization curves. The fatigue properties of laser welded Nitinol stents is compared to “unwelded” stents using accelerated radial compression as well as rotation and bending fatigue tests.
Summary: The authors discuss the status of joining NiTi-alloys to itself and to dissimilar materials. The role of process parameters on the microstructure of the weld, the heat affected zone and the tensile properties of laser welded tubing is discussed. The corrosion behaviour of laser welded Nitinol stents is assessed compared to “unwelded” stents via potentiodynamic polarization curves. The fatigue properties of laser welded Nitinol stents is compared to “unwelded” stents using accelerated radial compression as well as rotation and bending fatigue tests.
