Fatigue assessment of Ti-45Al-2Mn-2NbXD sub-element specimens

A novel test technique is described for the sub-element fatigue assessment of dovetail geometric features commonly employed as a fixture for blade/disc assemblies in steam and gas turbines. Once developed, the test method was employed to assess the performance of a model dovetail geometry employing the gamma titanium aluminide Ti-45Al-2Mn-2NbXD. In addition to generating information describing fatigue crack initiation, crack growth and ultimate failure, essentially via a trans-lamellar failure process, the associated wear processes were also characterised.