Evolution mechanism of microstructure and bond strength based on interface diffusion and IMCs of Ti/steel clad plates fabricated by double-layered hot rolling

Abstract

Ti/steel clad plates have good corrosion resistance and lower titanium cost. However, the low interfacial bond strength severely restricts their wide application. In this study, a new process is proposed for preparing Ti/steel clad plates with high bond strength by employing double-layered slab assembly and hot rolling. The effect of temperature on bond strength is systematically studied. The results show that the shear strength initially increases and then decreases with increasing temperature from 700 °C to 950 °C. The maximum strength value of 311 MPa is obtained at 850 °C with a reduction rate of 30% in a single pass. The mechanism analysis shows that the bond strength is affected by temperature in terms of metal deformation, elemental diffusion and intermetallic compound (IMC) formation. In addition, the shear strength depends on different degrees of dislocation strengthening and recrystallization in the titanium matrix when the fracture is located at titanium matrix near the interface. Finally, a phenomenological prediction mechanism-based model is developed to describe the relationship between the temperature and the bond strength. This research can provide guidance for the hot rolling preparation of Ti/steel clad plates with high bond strength. • Ti/steel plates were fabricated by double-layered slab assembly and hot rolling. • A superior bond strength of 311 MPa was obtained at 850 °C. • Microstructure evolution was characterized. • Bonding mechanism at different temperatures was analyzed. • A phenomenological prediction mechanism-based model was proposed.