目的 研究搅拌摩擦加工细晶Ti-6Al-4V合金在模拟海水中微观组织特征与腐蚀磨损性能的关系。方法 通过控制搅拌摩擦加工工艺（200 r/min-25 mm/min和200 r/min-50 mm/min）获得具有等轴细晶组织和片层状α相组织的Ti-6Al-4V合金。使用往复磨损试验机和电化学工作站，在模拟海水中对Ti-6Al-4V合金进行腐蚀磨损实验，获得摩擦系数-时间曲线、动电位极化曲线等一系列摩擦磨损和电化学曲线。使用激光共聚焦显微镜和扫描电子显微镜对磨痕进行观察，计算磨损率，并分析磨损机制。通过计算腐蚀磨损分量研究材料损耗的主要影响因素。结果 在腐蚀磨损中，因表面氧化膜被破坏，具有细晶结构的Ti-6Al-4V合金晶界面积大，腐蚀电位降低，但腐蚀电流密度小于原始试样。搅拌摩擦加工试样在腐蚀磨损实验中的摩擦系数更稳定，OCP条件下，具有细小等轴晶组织的搅拌摩擦加工Ti-6Al-4V合金的摩擦系数最低，磨损率较原始试样低20%。片层组织特征Ti-6Al-4V合金因微观力学性能各向异性而影响对磨球的行进路线，犁沟较混乱。原始样品的磨损机制主要为磨粒磨损和腐蚀磨损，搅拌摩擦加工后，样品在模拟海水中的磨损机制为磨粒磨损、分层磨损和腐蚀磨损。结论 等轴细晶组织Ti-6Al-4V合金在模拟海水中表现出低的磨损率和低的摩擦系数，该组织特征具有最优的耐腐蚀磨损性能。

The work aims to study the relationship between microstructure and tribocorrosion resistance of fine grain Ti-6Al-4V alloy by friction stir in synthetic seawater. Ti-6Al-4V alloy with equiaxed grains and fine lamellar sub-structure α phase was obtained by controlling the stir friction processes (200 r/min-25 mm/min and 200 r/min-50 mm/min). Tribocorrosion tests were conducted to Ti-6Al-4V alloy with reciprocating tribometer and electrochemical workstation in the synthetic seawater to obtain the coefficient of friction-time curves, potentiodynamic polarization curves, etc. Laser confocal microscope and field emission scanning electron microscope were used to observe the wear scar, calculate the wear rate and analyze the wear mecha-nism. The factors mainly including the material wear was investigated by calculating the corrosion components. During corrosion, the oxide layers of samples were destroyed and the Ti-6Al-4V alloy with fine grains occupied larger boundaries, the corrosion potentials decreased and corrosion current densities were smaller than that of original samples. Coefficient of friction curves of FSPed samples were stable. The FSPed sample with fine equiaxed grains showed the lowest COF and the wear rate after tribocorrosion test decreased by 20% compared with that of original samples. The FSPed Ti-6Al-4V alloy with fine lamellar sub-structure had chaotic furrows due to the influence of anisotropy of micromechanical properties on the travel route of grinding balls. The wear mechanisms of original samples were abrasive wear and corrosion wear, while those of FSPed samples in synthetic seawater were abrasive wear, delamination and corrosion wear. The FSPed Ti-6Al-4V alloy with fine equiaxed grains shows lower wear rate and low friction coefficient during tribocorrosion tests, so the structure characteristics have the best corrosion and wear resistance.