Cr4Mo4V轴承钢被广泛用于制造航空发动机主轴轴承，其在服役中的不稳定残余奥氏体会由于相变引起体积膨胀变形，从而影响轴承的尺寸精度和使用寿命。如何提升轴承钢中残余奥氏体稳定性，是本领域的重要研究内容。本研究通过外加磁场促进了偏聚在柯氏气团的碳原子向残余奥氏体的迁移，增加了残余奥氏体组织及力学稳定性，为提升轴承寿命与可靠性提供了一条新的技术路线，相关机理的研究丰富了外加磁场对材料热力学稳定性的研究，兼有科学与工程应用价值。本论文主要研究内容包括：1、对Cr4Mo4V钢开展了不同场强和脉冲次数下的磁场处理试验，评估出最优磁场处理参数，而后进行了磁场处理前后的硬度和室温压缩试验等力学性能测试。结果表明，Cr4Mo4V钢平均显微硬度从62.31 ± 0.44 HRC提高到63.04 ± 0.25 HRC。在2.5%工程压缩应变下残余奥氏体的相变情况表明，磁场处理使得残余奥氏体力学稳定性提高约3.5倍。2、针对淬火态Cr4Mo4V轴承钢，采用深冷处理和深冷-脉冲磁场耦合处理的对比，研究了磁场处理对残余奥氏体相变的影响和内在机制。结果表明，磁场处理使得样品在深冷条件下残余奥氏体绝对减少量从2.4 ± 0.3%下降到0.8 ± 0.8%。对两种样品进一步进行了回火处理，发现磁场处理试样的残余奥氏体含量仍能保持在15.4%左右，而不耦合磁场处理的样品含量为13.6 ± 0.5%，说明磁场提高了残余奥氏体的热稳定性。主要原因是磁场在深冷条件下对晶格收缩的缓解以及柯氏气团的解聚作用，令晶界附近位错和溶质原子得以分散，并使得残余奥氏体含碳量提高而稳定化。回火后细小碳化物析出减少，以及马氏体位错密度的下降进一步验证了该观点。3、利用动态热机械分析仪研究了室温磁场处理对Cr4Mo4V钢内耗行为的影响。应变谱结果表明，磁场使样品内耗在低应变下减小，而在高应变下变化不大；在温度谱中，磁场处理样品Snoek-Kê-Kóster峰的峰值内耗提高，峰温左移，相对峰宽减小。内耗行为的变化表明磁场处理有助于柯氏气团的解聚与碳原子向基体的重溶，影响了间隙原子与位错的交互作用，提高了基体强度和残余奥氏体稳定性，这为磁场处理提升轴承寿命与可靠性的机理研究提供了新的见解。

Cr4Mo4V bearing steel is widely used in the manufacture of main spindle bearings for aircraft engines. The phase transformation of unstable retained austenite during service can cause volume expansion deformation, thereby affecting the dimensional accuracy and service life of bearings. Enhancing the stability of retained austenite in bearing steel is an important research topic in this field. This study utilizes external magnetic field treatment to facilitate the migration of carbon atoms biased towards Cottrell atmosphere to retained austenite, increasing the thermal stability and mechanical stability of retained austenite. This provides a new technical route for improving bearing life and reliability, enriching the study of the thermodynamic stability of materials under external magnetic field, with both scientific and engineering application value.The main contents of the study include:1. Conducting an experiment on the magnetic field treatment of Cr4Mo4V steel under different magnetic field intensities and pulse counts and evaluating mechanical performance tests such as hardness and room temperature compression tests before and after magnetic field treatment after determining the optimal magnetic field treatment parameters. The results show that the average microhardness of Cr4Mo4V steel increased from 62.31 ± 0.44 HRC to 63.04 ± 0.25 HRC. The phase transformation of retained austenite under 2.5% engineering compression strain indicated that magnetic field treatment increased the mechanical stability of retained austenite by approximately 3.5 times.2. For quenched Cr4Mo4V bearing steel, a comparison between deep cryogenic treatment and deep cryogenic-magnetic field coupled treatment was conducted to study the effect and intrinsic mechanism of magnetic field treatment on the phase transformation of retained austenite. The results showed that the absolute reduction of retained austenite in samples under deep cryogenic conditions decreased from 2.4 ± 0.3% to 0.8 ± 0.8% after magnetic field treatment. Further tempering of both types of samples revealed that magnetic field treatment enabled the retained austenite content to remain around 15.4%, while the content in samples without coupled magnetic field treatment was 13.6 ± 0.5%, indicating improved thermal stability of retained austenite. The primary reason lies in the alleviation of lattice contraction under deep cryogenic conditions by the magnetic field, along with the disaggregation of Cottrell clusters, enabling the dispersion of dislocations and solute atoms near the grain boundaries. This process leads to an increase in the carbon content of retained austenite and facilitates its stabilization. The reduction in the precipitation of fine carbides after tempering and the decrease of dislocation density in martensite further supported this argument.3. The impact of magnetic field treatment on the internal friction behavior of Cr4Mo4V steel was studied using the dynamic mechanical analyzer. Strain spectra results showed that external magnetic field treatment reduced internal friction at low strains, with little change at high strains; in the temperature spectrum, the peak internal friction of the Snoek-Kê-Kóster peak in magnetic field-treated sample increased, the peak temperature shifted to the left, and the relative peak width decreased. The changes in internal friction behavior indicated that magnetic field treatment facilitated the disaggregation of Cottrell atmosphere and the re-solution of carbon atoms into the matrix, impacting the interaction between interstitial atoms and dislocations, leading to increased matrix strength and improved stability of retained austenite. These insights provide a new understanding for the mechanism of magnetic field treatment in enhancing bearing life and reliability.