TC11 titanium alloy was treated by laser shock peening (LSP)

while microstructure

residual stress and microhardness without/with LSP in different laser impacts were examined and compared via transmission electron microscope (TEM)

X-ray diffractometer and microhardness tester. The high-cycle vibration fatigue test of TC11 titanium alloy standard vibration specimens was conducted to verify effects of LSP on the high-cycle fatigue property. The results indicated that severe plastic deformation was formed and grains on the surface were refined with high-density dislocations

dislocation cells. Nanocrystals were generated successively with increasing laser impact. The maximum residual stress reached -632.5MPa in 10 impacts with 1500μm thick plastic deformation layer. The microhardness was increased by 19% with 700μm thick affected layer. The affected depth increased with the laser impact

but amplitude was limited. Fatigue limit of TC11 titanium alloy standard vibration specimens treated by LSP in 3 impacts had been improved from 483MPa to 593MPa.