Effect of Laser‐Deposition Repair Thickness on Fatigue Crack Growth Resistance in TA15 Titanium Alloy

In remanufacturing field, the laser deposition technology is widely used to repair the damaged surface of forged TA15 component. But the crack propagation behavior of the laser deposition repaired TA15 with different surface repair thicknesses is rarely investigated. Therefore, the crack propagation behavior of the laser deposition repaired TA15 with different surface repair thicknesses is characterized by the fatigue crack propagation rate (FCGR), plastic zone size, and energy release rate in this study. The experimental results show that the FCGR of the repaired specimen is reduced as the repair surface thickness increases. Besides, as the repair thickness augments, the crack propagation rate gradually approaches that of pure‐deposited TA15 test piece, indicating a significant influence of the repair area on crack propagation rate. As the repair thickness increases, the plastic zone size approaches that of the microstructure when crack propagation transitions into stable fracture. Simultaneously it is observed that a substantial accumulation of transient fractures consumes more energy, resulting in lower FCGR for the repaired area compared to TA15 substrate.