Segregation mechanism of alloying elements at the fcc-Fe/bcc-Fe interface and its effects on carbon diffusion across the boundary

Understanding the structure and energetics of the fcc/bcc phase interface is essential for lightweight design using advanced high strength steels (AHSSs). The present work investigated the solute segregation and its effects on the interfacial properties of fcc-Fe/bcc-Fe interface utilizing the first-principles calculations. The convergence of fcc-Fe (111) and bcc-Fe (011) slabs was examined, and a 7-layer slab was selected to construct the fcc/bcc interface based on K–S relationship. Then, the segregation behavior of various alloying elements at the interface and the consequent impact on the work of adhesion and interfacial energy were explored. The diffusion behavior of carbon atoms across the interface under the effect of segregation was also investigated. The findings provide theoretical guidance for regulating carbon partitioning via interface engineering and optimizing the design of AHSSs.