Fractographic Analysis of 60-Nitinol Bearing Races

Abstract: Fracture surfaces on a failed bearing race made from 60-Nitinol (60 wt% Ni – 40 wt% Ti) were analyzed. The bearing had experienced excessive localized heat due to an issue during machining that may have resulted in dimensional distortion. However, the classical fracture features that were identified by scanning electron microscopy and the fracture origins coincided with high concentrations of TiC-based contamination. Lessons learned for processing and quality control are discussed. An attempt…