The prediction of fatigue life at notches in the near alpha titanium alloy Timetal 834

The anisotropic mechanical response of the titanium alloy Timetal 834 is explored through room temperature strain controlled low cycle fatigue tests employing plain specimens under pure tension and torsion loading modes. These data are then utilised to predict the performance of two notched specimen geometries which can be considered as pseudo components representative of typical engineering stress raisers. The role of multi-axial stress fields at the notch root is considered through specific predictions based on the tension and torsion data. Plain and notched low cycle fatigue data are found to correlate when analysed using stabilised and peak elastic stress criteria respectively. The effect of critically stressed volume is further explored through consideration of a third notch geometry containing a relatively sharp notch/small root radius.