STRENGTHENING Ti-15-3: DISCOVERING THE FATIGUE-BOOSTING WONDERS OF LASER SHOCK PEENING

Laser shock peening (LSP) is a promising surface modification technique used to enhance the surface properties of material. This study investigates the impact of laser shock peening without a protective coating (LPwC) on the fatigue behavior of the duplex-aged (DA) Ti-15-3 alloy with a power density of 9[Formula: see text]GW/cm2 power density and a wavelength of 1064[Formula: see text]nm. The application of laser shock peening without Coating (LPwC) resulted in the development of a titanium oxide layer on the surface of the material, a change that was not seen in the untreated samples and is linked to the high-energy nature of the laser treatment. The untreated DA specimens displayed a compressive residual stress (CRS) of −198 MPa at the surface, which shifted to tensile stress at a depth of 100[Formula: see text][Formula: see text]m. In comparison, the samples subjected to laser peening exhibited a significant increase in CRS, reaching [Formula: see text] MPa at the same depth. Furthermore, the hardness of the surface rose from 350[Formula: see text]HV in the untreated samples to 546[Formula: see text]HV in those that underwent laser peening, emphasizing the work hardening induced by the treatment. Results from axial fatigue testing demonstrated that LPwC markedly improved the fatigue life of the Ti-15-3 alloy, attributed to the combined effects of CRSs, work hardening, and changes in microstructure. These findings highlight the substantial promise of LPwC as a surface treatment method for enhancing the fatigue resistance of DA Ti-15-3 alloy, which is crucial for applications in aerospace and defense. The insights gained can serve as a basis for refining laser peening parameters to further enhance the material’s performance.