目的 预测和评估激光冲击强化TC17钛合金叶片的高周疲劳强度。方法 测试表面激光强化后的硬度和残余应力分布，开展拉伸和振动疲劳试验，分析硬度和残余应力演化规律，基于内部疲劳极限理论和临界距离理论，建立考虑表面完整性的强化叶片疲劳极限预测模型，结合有限元模态数值仿真，对表面强化后的钛合金叶片高周疲劳强度进行预测。结果 板状拉伸试样的疲劳试验结果表明，表面强化后钛合金材料的疲劳极限提升13.41%。模拟叶片试样的弯曲振动疲劳试验结果表明，表面强化后叶片的疲劳极限提升7.77%。基于内部疲劳极限理论，结合硬度和残余应力试验结果，确定危险点位于距表面80 μm处。针对危险点处，基于临界距离理论开展叶片疲劳极限预测，模型预测精度误差不超过15%。结论 表面激光强化可以有效提升TC17钛合金材料和叶片的高周疲劳极限。本文建立的表面强化叶片疲劳极限预测模型，能够精确预测具有复杂曲面结构的表面强化叶片的高周疲劳极限，可以为喷丸强化、激光强化、激光冲击+喷丸复合强化等多种强化方式的叶片疲劳性能评估提供参考。

Fan and compressor blades are the critical components of aircraft engines. The surface strengthening treatment process is widely used in blade manufacturing. It is important to predict the high cycle fatigue strength of blades after surface strengthening for blade manufacturing. However, the irregular geometric shape of the blades and the complex surface state and microstructure such as hardness and residual stress after surface strengthening pose challenges for the fatigue performance evaluation of surface strengthened blades. This work aims to study the fatigue strength evaluation of surface laser shock peened TC17 titanium alloy blades. Firstly, the microhardness and residual stress distribution of the blade surface after strengthening were tested. Then, surface strengthened blade fatigue tests were carried out to test the fatigue strength and analyze the evolution law of microhardness and residual stress. Based on the internal fatigue limit theory and critical distance theory, a surface strengthened blade fatigue limit prediction model considering surface integrity was established. Combined with finite element modal numerical simulation, the high cycle fatigue strength of surface laser shock peened titanium alloy blades was predicted, which provided theoretical guidance for the fatigue performance evaluation of surface strengthened blades. The surface laser shock peening could improve the high cycle fatigue limit of TC17 titanium alloy material and simulated blades. The tensile fatigue test results of the plate-like tensile specimen showed that the fatigue limit increased by 13.41% after surface strengthening. The fatigue test results of simulated blade bending vibration showed that the fatigue limit increased by 7.77% after surface strengthening. The microhardness results showed that the microhardness of TC17 substrate before laser shock peening was 353HV0.2. After laser shock peening, the surface microhardness of TC17 increased to 394.5HV0.2, and the depth of the affected layer was 800 μm. After fatigue loading, the surface microhardness decreased to 374.8HV0.2, and the depth of the affected layer also decreased from 800 μm to 100 μm. The residual stress results showed that the affected depth of laser shock peening on the residual stress of TC17 titanium alloy was about 300 μm. After cyclic loading, the residual stress on the surface of specimen relaxed and the residual compressive stress layer became shallower. At a depth of about 100 μm, the residual stress value was about –70 MPa, which was equivalent to the initial residual stress value of the substrate, and the influence depth after relaxation was about 120 μm. Based on the internal fatigue limit theory and critical distance theory, a surface strengthened blade fatigue limit prediction model considering surface integrity was established with 7 steps, with a prediction accuracy error of no more than 15%. This study can provide theoretical guidance for evaluating the fatigue performance of surface strengthened components with complex geometric structures and various strengthening methods, such as shot peening, laser shock peening, laser shock peening and shot peening compound strengthening.