目的 分析重载铁路车轮材料磨损与滚动接触疲劳损伤的失效机制。方法 用维氏硬度计在现场失效车轮横截面上测量轮缘、名义滚动圆及外轮辋处的表面硬度分布。用线切割机在车轮轮缘、名义滚动圆、外轮辋处分别沿纵剖面及横截面切割车轮，将试样经金相处理后进行微观分析。利用光学显微镜和扫描电子显微镜观测车轮材料表面及剖面损伤。结果 踏面剥离车轮名义滚动圆及外轮辋处的加工硬化层深度为磨耗过限车轮的约2倍;磨耗过限车轮和踏面剥离车轮损伤失效最严重的区域均在踏面名义滚动圆处，而轮缘与外轮辋相对较轻微;磨耗过限车轮名义滚动圆处疲劳裂纹较小、较浅，且均匀分布于车轮纵剖面，而踏面剥离车轮疲劳裂纹近乎遍布整个车轮剖面，多条裂纹交织形成网状裂纹。踏面剥离车轮在名义滚动圆处的加工硬化层深度、最大裂纹角度、最大裂纹长度及最大裂纹深度分别可达6 mm、90°、2.5 mm、1 mm，分别约为磨耗过限车轮的2、2.5、2、1.5倍。结论 磨耗过限车轮损伤失效起因是较大且频繁的轮轨接触应力所导致的车轮踏面凹形磨耗，改变了轮轨接触状态，进而导致车轮材料失效。踏面剥离车轮损伤形成的根本原因是多条疲劳裂纹的萌生并持续扩展，最终交织形成大面积网状裂纹，进而导致材料破碎。同时，外界环境的水介质进入裂纹中会改变裂纹扩展方向，并加速裂纹的扩展。磨耗过限车轮廓形磨损程度大于踏面剥离车轮，而其滚动接触疲劳损伤程度小于踏面剥离车轮，即车轮现场服役中材料磨损与滚动接触疲劳间存在互相制约的关系。

The increase in train speed and axle loads leads to increasingly significant wheel-rail rolling contact fatigue and wear. Wheels play a role in load-bearing, guiding, and transmitting traction/braking force during operation, and are the core components that ensure the safety of railway trains. Damage forms of train wheels can be divided into several major types, including wheel tread wear, wheel flange wear, rolling contact fatigue, tread spalling and dents. If wheel damage is not timely controlled, it will accelerate wheel-rail vibration, affect service comfort and even induce damage to other parts of the wheel axle. Therefore, the analysis of failure mechanism of in-situ failed wheel materials can provide theoretical support for wheel maintenance.