titanium sponge following two conditions are running low stress

Two conditions determine the titanium material defects control
  Like all other materials titanium sponge titanium, there is no guarantee non-destructive testing methods test out all the flaws in titanium, because some defects may be too small and some defects may use non-destructive testing techniques can not be found, it must be made ​​on titanium parts now given a suitable defect tolerance limits. For defects within the permissible limits of control, you must first meet the following two conditions are running low stress; followed by the best microstructure.
     Best microstructure of small cracks or small defects are not sensitive to prevent further expansion of these tiny cracks and titanium defects. Passivation of the crack tip can be used, titanium alloy pump the crack away from the plane of maximum stress and cause cracks and other penny a way to stop the expansion of any large cracks. After the adoption of these measures will reduce the stability of the fatigue crack growth rate and fracture toughness can be improved.