Effect of Peening Media Type on the High-Cycle Tensile-Tensile Fatigue Properties of Ti-6Al-4V Alloy by Ultrasonic Shot Peening

This study investigates the effect of ultrasonic shot peening (USP) on Ti-6Al-4V samples using cast steel and zirconia ceramic shots at the same intensity. The surface integrity of the samples before and after treatment was characterized, and tensile-tensile fatigue tests were conducted under various stress amplitudes to compare the improvements in fatigue performance. The mechanisms underlying the enhancement of fatigue properties were analyzed by examining microstructural changes and fracture morphologies. The results show that, compared to steel shot, zirconia ceramic shot leads to lower surface roughness, finer surface grains, and more significant work hardening and plastic deformation. These factors contribute to a more pronounced improvement in the fatigue performance under tension-tension loading of Ti-6Al-4V under USP treatment. The superior performance of ceramic shot can be attributed to low density combined with high hardness of the ceramic shot.