| Abstract Scope |
Low-carbon, microalloyed, cost-effective dual-phase (DP) steels offer significant potential for automotive load-bearing structures, serving as viable alternatives to expensive second-generation high-alloy advanced high-strength steels (HAG-AHSS). These DP steels can achieve comparable strength, ductility, and formability while eliminating issues like segregation, poor weldability, processing challenges, and high costs associated with HAG-AHSS. Since automotive components experience fatigue loading, understanding the high-cycle fatigue (HCF) behavior of DP steels is critical. In this work, ferrite–martensite DP steel sheets with superior mechanical properties were developed using advanced thermomechanical processing. HCF testing was performed to examine fatigue behavior, with a focus on the influence of microstructure and crystallographic texture. Characterization techniques such as electron backscatter diffraction (EBSD) in FESEM and X-ray diffraction were used. Key microstructural parameters including ferrite grain size, martensite volume fraction, dislocation density, boundary types, and crystallographic texture were systematically correlated with fatigue endurance limits. |