轴承是航空发动机里最重要的连接部件，可以高效、平稳地实现航空发动机的支撑功能，轴承的质量对于航空发动机的性能至关重要。由于轴承在较高的温度下服役，这要求轴承材料具有较好的高温硬度和强度，保持良好的热稳定性。M50是我国最普遍使用的高温轴承钢，但其在服役温度下的硬度和强度还有待进一步提高。因此，本文将在M50钢的基础上依据钢的强化方式进行合金成分设计、组织调控与性能优化，以期开发出性能更优异的航空发动机轴承用钢。W元素是耐热钢和高速钢中的典型元素，能够减小碳化物形成元素的扩散系数、降低碳化物与基体间的界面能，从而减缓组织中碳化物的粗化速率，因此W极有可能通过细化钢中碳化物尺寸来优化组织进而提高轴承钢的高温力学性能。对此，本文对M50高温轴承钢进行了W微合金化，采用计算模拟方法、多种表征手段以及拉伸、压缩、硬度等性能测试实验，系统研究了W微合金化对M50高温轴承钢的碳化物组织、基本力学性能的影响规律。组织表征和力学测试实验的研究结果表明，W元素在M50钢中主要与C元素结合形成尺寸更小的M6C型碳化物。1.5wt% W元素的添加大幅度降低了M50钢组织中一次碳化物的长轴平均尺寸和长宽比，一次碳化物的形状由长杆状变为椭球状，同时显著降低了二次碳化物的平均直径，增加了二次碳化物的数密度和体积分数。进而提高了M50钢的强度、高温硬度和刚度，并且减小了硬度随温度升高而降低的幅度值，使M50钢的热稳定性增加。因此，W微合金化可实现M50钢中碳化物的细化，进而有效提高材料的基本力学性能。计算模拟研究结果表明，W元素能够降低M50钢中M6C、M2C、M23C6和MC析出相与基体的界面能、增大M2C、M6C和M23C6型碳化物的形核化学驱动力，进而能够增加析出碳化物的体积分数和数量密度；W元素还能降低Mo、W、V、Cr和C等碳化物形成元素的扩散系数、减缓M6C、M2C、M23C6和MC型碳化物的粗化速率，进而减小碳化物的尺寸。因此，W元素通过影响碳化物形核、长大和粗化的整个过程来影响碳化物最终的尺寸和数量。

Bearing is the most important connecting component in an aeroengine, which can efficiently and smoothly achieve the support function of the aeroengine. The quality of the bearing is crucial to the performance of the aeroengine. Due to service at higher temperatures, bearings are required to have good high-temperature hardness and strength, and maintain good thermal stability. M50 is the most commonly used high-temperature bearing steel in China, but its hardness and strength at service temperature still need to be further improved. Therefore, this article will conduct alloy composition design, microstructure control, and performance optimization based on the strengthening methods of M50 steel, with a view to developing better performance aviation engine bearing steel.W element is a typical element in heat-resistant steel and high-speed steel, which can reduce the diffusion coefficient of carbides forming elements, reduce the interfacial energy between carbides and the matrix, and thus slow down the coarsening rate of carbides in the structure. Therefore, W is highly likely to improve the high-temperature mechanical properties of bearing steel by refining the size of carbides in the steel. In this paper, we conducted W microalloying on M50 high temperature bearing steel, and systematically studied the effect of W microalloying on the carbide structure and basic mechanical properties of M50 high temperature bearing steel using computational simulation methods, various characterization methods, and tensile, compressive, and hardness testing experiments.The results of structural characterization and mechanical testing experiments show that W element mainly combines with C element in M50 steel to form smaller M6C type carbides. 1.5wt% W significantly reduces the average size in the long axis direction and length-width ratio of the primary carbide in the microstructure of M50 steel, and the shape of the primary carbide changes from a long rod to an ellipsoidal shape, at the same time, the average diameter of the secondary carbide is significantly reduced, and the numerical density and volume fraction of the secondary carbide are increased. This further improves the strength, high-temperature hardness, and stiffness of M50 steel, and reduces the magnitude of the decrease in hardness as temperature increases, resulting in an increase in the thermal stability of M50 steel. Therefore, W microalloying can achieve the refinement of carbides in M50 steel, thereby effectively improving the basic mechanical properties of the material.The calculation results show that W element can reduce the interface energy between M6C, M2C, M23C6 and MC precipitates and the matrix in M50 steel, increase the nuclear chemistry driving force of M2C, M6C and M23C6 type carbides, thereby increasing the volume fraction and quantity density of precipitated carbides. Besides, the W element can also reduce the diffusion coefficient of carbides such as Mo, W, V, Cr, and C, slow down the coarsening rate of M6C, M2C, M23C6, and MC type carbides, thereby reducing the size of carbides. Therefore, the W element affects the final size and quantity of carbides by influencing the entire process of carbide nucleation, growth, and coarsening.