Fatigue strength of titanium and titanium alloys
In general the commercially pure titanium grades display fatigue strength levels in the unnotched condition of between 60 and 75% of tensile strength. The titanium alloys have values of around 50%. In the hardened condition the fatigue strength values of the alloys drop to as low as 20%, and so the absolute values in the annealed condition are frequently higher.
As fatigue strength depends on a large number of parameters, to which forming conditions and microstructure are added in the case of the titanium alloys, the figures given below for the fatigue properties of the titanium alloy TiAl6V4 (TIKRUTAN LT 31) are for guidance only: