Modelling of fatigue-corrosion in Ti6246 alloy at 500°c

This paper deals with a study of the influence of the atmospheric environment on the resistance against fatigue crack propagation of a Ti6246 titanium alloy at 500°C. Tests were performed in the near‐threshold and mid‐rate ranges under controlled gaseous environments, including vacuum and argon, with controlled partial pressures of water vapour and oxygen. A predominant detrimental influence of water vapour is demonstrated even under very low partial pressure, while oxygen gas is shown to moderate the influence of water vapour. A crack‐propagation model relating the growth rate to the effective stress intensity factor range is proposed to account for this competitive influence of water vapour and oxygen with respect to the test frequency.