Multiaxial thermo-mechanical fatigue damage mechanism of TC4 titanium alloy

In this paper, the experimental investigation was carried out on the TC4 titanium alloy to understand the cyclic deformation behavior and fatigue damage mechanism of materials under multiaxial thermo-mechanical loading. The results showed that the fast cracking mode of the material may be activated by the combined action of high temperature, tensile stress and shear stress, inducing a fast degradation in the axial mechanical properties of the material, which results in a drastic decrease in the failure life of the material. Moreover, it is also found that the non-proportional additional hardening and the tensile mean stress can increase the fatigue and oxidation damages of the material, and the material damage behavior is temperature dependent and time dependent. It should be pointed out that the damage mechanisms identified in this paper can reasonably explain the life law under uniaxial isothermal fatigue loading with and without dwell time, uniaxial and multiaxial thermomechanical fatigue loadings.

Automated summary

This paper presents an experimental investigation on the cyclic deformation behavior and fatigue damage mechanism of TC4 titanium alloy under multiaxial thermo-mechanical loading. The results reveal that the combined action of high temperature, tensile stress, and shear stress can activate the fast cracking mode of the material, causing a rapid degradation in its axial mechanical properties and a significant decrease in its failure life. Additionally, non-proportional additional hardening and tensile mean stress contribute to the fatigue and oxidation damages of the material, with the material's damage behavior being temperature and time dependent.