TC17钛合金叶片振动疲劳寿命研究

Blades are typical thin-walled curved components that operate in harsh environments. Under the action of alternating stress, fatigue fracture occurs after a certain number of cycles, which seriously affects the reliability and durability of the engine. In order to study the fatigue performance of blades under vibration, the blades were processed with different process parameters, and their surface roughness, residual stress, and microhardness were tested. The vibration fatigue tests and fatigue fracture analysis of the blades were also performed. The results show that the dangerous position of the TCI7 titanium alloy blade is on the back of the blade, 48. 1 mm from the blade tip and 26. 9 mm from the air inlet edge; the surface roughness of the blade is 0. 373 μm, the surface stress concentration coefficient is 1.014, the surface residual stress is - 319. 38 MPa, and the surface microhardness is 412. 53 HV. The highest fatigue life of 8. 91 × 10 cycles was obtained when the surface residual stress was considered. The residual stress has the most significant effect on the fatigue life of the blade, followed by the surface stress concentration coefficient, and then the microhardness. The fatigue failure mode of the milled blade is a surface single-source start, and in the fatigue source area, there are obvious radiation characteristics, in the crack extension area, there are fatigue stripes and secondary cracks, and the instantaneous fracture area is of toughness characteristics, which belongs to toughness fracture.