Defect behavior in gamma titanium aluminides

An experimental study was performed to demonstrate the effect of a wide variety of defect and damage types on the tension and fatigue strength of two different gamma alloys. Overall it was observed that the strength in the presence of the defects studied was reduced to no less than 75% of the baseline or undefected level in tension and to 70% in fatigue. The response of the two alloys, one a high strength fine microstructure wrought alloy and the other a lower strength coarse grained cast alloy, were surprisingly similar in terms of defected strength as a percentage of the undefected baseline strength. This is encouraging for the use of higher strength alloys in applications requiring defect or damage tolerance.