Interfacial Reaction Products and Mn/Mo-Regulated TiC(001)/γ-Fe(001) Interfaces in Titanium–Steel Clad Plates: A First-Principles Investigation

Abstract

: Titanium–steel clad plates combine the corrosion resistance of titanium alloys with the strength and cost advantages of stainless steels, making them attractive for advanced structural applications. However, interfacial reactions during fabrication or service may lead to the formation of Fe–Ti intermetallic compounds and TiC, which strongly affect interfacial bonding and mechanical reliability. In this work, first-principles calculations were performed to investigate the structural stability, mechanical properties, and electronic bonding characteristics of typical interfacial reaction products, including FeTi, Fe 2 Ti, and TiC, in TC4/316L stainless steel clad systems. The results show that all three phases are thermodynamically and mechanically stable at 0 K. TiC exhibits the highest hardness and elastic modulus due to its strong Ti–C covalent bonding; however, its limited ductility may compromise interfacial deformation compatibility when it forms as a continuous brittle layer. In contrast, a stable and discontinuous TiC phase at the TiC/γ-Fe interface may provide favorable conditions for γ-Fe heterogeneous nucleation. The calculated segregation energies indicate that Mn and Mo tend to segregate at the TiC/γ-Fe interface. Among the considered configurations, the X-4 doping mode provides the highest work of adhesion, suggesting enhanced interfacial bonding. These results suggest that Mn and Mo can modify the local bonding environment of the TiC/γ-Fe interface and potentially enhance TiC-assisted γ-Fe interfacial stability when the favorable configuration is achieved. However, the overall performance of titanium–steel interfaces is also influenced by the concurrent formation and distribution of other interfacial reaction products. This study provides atomic-scale insight into the interfacial reaction products and alloying-element regulation mechanisms in titanium–steel clad plates.