Defect Tolerance Of A Gamma Titanium Aluminide Alloy

The fatigue properties of a Ti-48Al-2Cr-2Nb alloy obtained by electron beam melting (EBM) with a patented process has been examined by conducting high cycle fatigue tests performed at different loading ratios at room temperature. Fatigue crack tests have been performed for the purpose of characterizing the fatigue crack growth rate and threshold of the material. In order to assess the sensitivity of the material to the presence of defects and to adopt suitable fatigue design criteria, fatigue tests with artificial defects have been also performed with different defect size and loading ratio. Fatigue tests have been interpreted by the adoption of a suitable model based on the small crack approach, highlighting individual fatigue characteristics of the studied TiAl alloy. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ICM11