目的 提高TC11钛合金的使役性能，对LSP技术在钛合金航空构件上的推广应用提供试验依据和技术支撑。方法 利用激光冲击强化(LSP)技术对片层组织的TC11钛合金进行表面纳米化处理，激光能量为6 J，脉宽为20 ns，光斑直径为3 mm，搭接率为50%。借助X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线应力分析仪、显微硬度计及拉伸试验机对TC11钛合金LSP前后的微观组织及力学性能进行表征。结果 经LSP处理后，在TC11钛合金表层形成了梯度纳米结构，其中外表层晶粒尺寸约为10 nm，形变层厚度约为200 μm;在次表层组织中形成了大量位错缠结、形变孪晶及层错等晶体亚结构缺陷。LSP后钛合金表层存在着最大残余压应力(–267 MPa)和显微硬度值(425HV)，且随着距表层距离的增大，相应的数值均呈现出逐渐减小的趋势。此外，LSP后TC11钛合金的抗拉强度和屈服强度分别提高了19.4%、18.3%，但伸长率略有下降，断口形貌从典型的韧性断裂向准解理和韧性混合型断裂转变。结论 在LSP作用下获得的梯度纳米结构和残余压应力的共同作用下，TC11钛合金获得了良好的强度–塑性匹配。

The paper aims to improve the serviceability of TC11 titanium alloy and provide experimental basis and technical support for the popularization and application of LSP technology in aeronautical component of titanium alloy. The surface of TC11 titanium alloy with lamellar structure is nanocrystallized by laser shock peening (LSP). The pulse energy is 6 J, the pulse width is 20 ns, the spot diameter is 3 mm, and the overlap ratio is 50%. The microstructure of TC11 titanium alloy before and after LSP are characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM). Compressive residual stresses in different depth were measured by x-ray stress analyzer. The microhardness of different depth is measured by microhardness tester. The mechanical properties are tested by tensile tester. Finally, the fracture morphology is photographed by SEM. The results show that gradient nanostructures are formed on the surface of TC11 titanium alloy after LSP, in which the grain size of the uppermost layer is about 10 nm, and the thickness of the deformation layer is about 200 μm. A large number of crystal substructure defects such as dislocation tangles, deformation twins and stacking faults are formed in the subsurface layer. The maximum compressive residual stress and microhardness exist in the surface layer of titanium alloy after LSP. The surface residual stress is about –267 MPa, the surface microhardness is about 425HV, and the corresponding values decrease gradually with the increase of the distance from the surface. In addition, the tensile strength and yield strength of TC11 titanium alloy after LSP are 1293 MPa and 1162 MPa respectively, which are 19.4% and 18.3% higher than those before LSP. But the elongation decreases slightly, about –8.9%. The fracture morphology changes from typical ductile fracture to quasi-cleavage and ductile mixed fracture. Under the combined action of gradient nano-structure and residual compressive stress after LSP, LSP-TC11 titanium alloy obtains good strength-plasticity matching.