Abstract:The fatigue crack growth rate of TA15 titanium alloy was measured by laser deposition using standard CT samples, and the fatigue crack growth mechanism was analyzed by combining the microstructure, crack propagation path and fracture morphology. Based on the method of ABAQUS and FRANC 3D co-simulation, the stress intensity factor of the crack tip was simulated and the life prediction was carried out. The results show that the crack propagation rate of the laser deposition manufacturing state is lower than that of the forging state, and the crack mainly passes through the lamellar α phase (α_l), and a small amount propagates along the α_l, and the fatigue fringes are clearly visible in the stable propagation zone, accompanied by a large number of secondary cracks, and the instantaneous fracture zone is a typical ductile fracture. On the other hand, the stress intensity factor calculated by ABAQUS and FRANC 3D co-simulation is in good agreement with the theoretical value, and the relative error of the predicted life is less than 5%, which confirms the conservatism of the prediction results, verifies the reliability of the simulation analysis, and ensures the safety in engineering applications.

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