Numerical Modeling of Crack Initiation From Interface Between Second‐Phase Particles and Carburized Gear Steel During Contact Fatigue

The impact of second‐phase particles on contact fatigue has been recognized, particularly in carburized steels, where crack initiation is often localized around these particles. This study aims to investigate the role of interfacial properties between second‐phase particles and the matrix in governing contact fatigue crack‐initiation life. A numerical framework was developed combining finite element simulations, cohesive zone modeling, and continuum damage mechanics to evaluate the influence of particle attributes and interfacial characteristics. Results indicate that interfacial stiffness is the dominant factor affecting stress distribution and crack‐initiation life, with interfacial discontinuities playing a critical role in enhancing local stress concentrations. Moreover, machine learning tools CatBoost coupled with SHAP value analysis were employed to quantify and rank the contributions of various parameters. This study highlights the significant influence of interface properties, particularly interfacial stiffness, on the fatigue behavior of second‐phase particles and provides valuable insights into optimizing material performance by controlling interface characteristics.