Experiments and numerical simulations for the fatigue behavior of a novel TA2-TA15 titanium alloy fabricated by laser melting deposition

摘要

In this paper, experiments and numerical simulations are conducted to investigate the fatigue behavior of a novel TA2-TA15 titanium alloy fabricated by the laser melting deposition (LMD) manufacturing process. First, the uniaxial tensile and fatigue experiments of the LMD TA2-TA15 specimens are carried out to acquire the basic static mechanical and fatigue properties, and the experimental results show that the values of Young's module, yield stress, ultimate stress and fatigue limit of the LMD TA2-TA15 material are between that of the TA2 and TA15 materials. Moreover, the dispersion of data in the experimental fatigue lives are observed, and then the fracture surfaces of the LMD TA2-TA15 specimens are tested by the scanning electron microscope (SEM), revealing that the dispersion is primarily caused by the multiple sources of cracks and the manufacturing defects inside the specimens. After that, several recommendations are provided for the better applications of different titanium alloys based on the engineering requirements and economy consideration. At last, the fatigue lives are numerically predicted for the LMD TA2-TA15 titanium alloy, which are compared with the experimental data. The further investigations of the predicted fatigue damage behavior indicate that the damage variable and the damage evolution rate increase fast with the increase of the number of cycles, resulting in the rapid decrease of the Young's modulus and the von Mises stress, when the loading cycles reach to 90% of the fatigue life.