The effect of single and multiple overloads on the fatigue crack growth of high strength titanium aluminides

Samples of fully lamellar titanium aluminides with randomly orientated colonies were exposed to single and multiple overloads. Damage was monitored by acoustic emission to determine its extent, its microstructural location, and to consider how damage may be introduced under single and multiple loading. The samples were then exposed to cyclic fatigue so as to evaluate any effects of these overloads upon subsequent fatigue life. After fatigue detailed microstructural and fractographic evaluation has been carried out.