Abstract:To address the failure caused by surface corrosion fatigue of titanium alloy structural components and to extend the service life of titanium alloys used in aircraft structures, Supersonic fine particle bombardment (SFPB) technology was applied to the hot-rolled Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy with varying impact times. This process created a gradient nanostructure on the surface of the samples, and various instruments and equipment were used to study the effects on the microstructure, microscopic morphology, and mechanical properties after different treatment times. At an SFPB treatment time of 60 s, the surface average nanocrystal grain size of the hot-rolled structure was minimized, measuring 30.4 nm. The surface roughness of the treated samples increased compared to the original ones, with the minimum surface roughness occurring at 60 s. However, longer impact times led to the formation of microcracks on the sample surface. The SFPB treatment introduced high compressive residual stress on the sample surface, resulting in a significant increase in microhardness. After the SFPB treatment, the sample"s strength increased, with a slight decrease in elongation before stabilizing. At a treatment time of 60 s, the best combination of strength and plasticity was achieved. The corrosion fatigue life of the SFPB-treated samples was improved by 12.7 times compared to the untreated samples. The SFPB treatment was able to generate a gradient nanolayer near the surface of the TA15 titanium alloy, significantly enhancing its tensile properties and corrosion fatigue life.