目前，我国高速动车组车轴材料仍然依赖进口，其国产化研究选择使用合金钢，而与之匹配的表面强化工艺研究相对滞后，同时，基于传统疲劳极限的车轴设计规范已无法保证其服役安全性。本研究针对高速动车组合金车轴钢开展新型微粒子喷丸强化机理研究，研究喷丸参数与表面性能的关系，仿真微粒子喷丸过程和残余应力分布，分析表层残余应力的稳定性，建立基于材料性能和载荷的残余应力松弛模型。同时，研究微粒子喷丸工艺对超高周疲劳性能的影响，阐明微粒子喷丸处理对合金车轴钢表面和内部裂纹萌生机制以及两种裂纹扩展竞争机制的影响，确定与其匹配的抗超高周疲劳的工艺参数。明确变载荷作用下的疲劳性能，建立变幅载荷作用下的累计疲劳损伤模型。研究不同裂纹萌生机制共存下的概率S-N曲线模型，建立超高周疲劳可靠性评估方法。本研究可以为国产化合金车轴表面强化处理工艺选择，可靠性设计和寿命预测提供指导。

The material applied to China's high-speed multiple units axle is still imported and the alloy steel is the selected material for the domestic research, while the surface strengthening method matching with the material is comparatively lagging. Meanwhile, the axle design standard, which is still based on the conventional fatigue limit, cannot guarantee its service safety. In this study, the strengthening mechanism of micro-shot peening on the alloy axle steel for high-speed multiple units is carried out; the relationship between micro-shot peeing parameters and surface properties is studied; the micro-shot peening process and residual stress distribution are simulated; the reliability of the residual stress is analyzed and the relaxation model based on the material properties and loading stress is established; meanwhile, the very high cycle fatigue tests are conducted to study the influence of micro-shot peening on fatigue properties; the effect of micro-shot peening on initiation mechanism for surface crack and internal crack as well as the propagation competing mechanism between them is clarified. Then the micro-shot peening parameters matching with the alloy axle steel to improve the very high cycle fatigue property is determined. Besides, the fatigue property under variable amplitude loading is analyzed and the fatigue cumulative damage model is proposed. The probability S-N curve model with different crack initiation mechanism is studied and the reliability evaluation method for very high cycle fatigue is established. The results of this study can supply information for surface strength treatment selecting, probability design and fatigue life prediction for localization alloy axle.