Fatigue Testing of a New Generation Commercial Scale Ultra-Low Inclusion NiTi Alloy

The effects of inclusions within a Nitinol alloy on the fatigue performance has been largely accepted by the Nitinol community. With significant reduction in size and density of non-metallic inclusions, the statistical probability of an inclusion being at the region of high stress and facilitating fatigue failure is much reduced. A new generation of commercial scale, ultra-low inclusion Nitinol material has been developed. The purpose of this study was to characterize this new alloy and demonstrate the improved fatigue performance. It was shown that a significant improvement fatigue performance can be realized with the new commercial scale ultra-low inclusion NiTi alloy. The results further suggest that inclusion size and density play a critical role in fatigue performance.