Creep-fatigue damage behavior of a titanium alloy at room temperature: Experiments and modeling

In this paper, the creep-fatigue failure mechanism and damage behavior of a Ti-6Al-3Nb-2Zr-1Mo titanium alloy at room temperature were quantitatively investigated with a series of fatigue and creep-fatigue tests. Based on experimental data and continuum damage mechanics theory, a phenomenological creep-fatigue damage model applicable to Ti-6Al-3Nb-2Zr-1Mo titanium alloy at room temperature is proposed that can describe the stress dependence of the interaction between fatigue damage and creep damage. The proposed model can consider the mutual effects of fatigue damage and creep damage at room temperature. Remarkably, the previous damage models proposed based on creep-fatigue experiments at high temperatures cannot accurately characterize the creep-fatigue damage behavior of titanium alloys at room temperature. Creep damage accumulates at a fast rate and dominates the damage evolution in the initial stage, and fatigue damage predominates in the late stages. The fatigue life is significantly reduced by creep damage at room temperature. Moreover, fatigue and creep damage promote each other.