Investigation on the interfacial microstructure and mechanical properties of Ti alloy/HSLA steel clad plates fabricated by vacuum roll-cladding

Abstract

The titanium (Ti) alloy/high-strength low-alloy (HSLA) steel clad plate was successfully fabricated by vacuum roll-cladding (VRC), and the effect of heating temperatures on the interfacial microstructure and mechanical properties was studied. The type and distribution of the interfacial intermetallic compounds (IMCs) were the main factors affecting the mechanical properties of the clad plate. Results showed that the TiC particles and clusters formed the nonuniform interface when heated at 850 °C, which tended to cause stress concentration during the shear deformation and resulted in lower bonding strength. A large number of TiC particles and tiny FeTi grains were formed at 900 °C, leading to the best shear strength (320 ± 25 MPa). However, the FeTi was formed adjacent to β-Ti, and the TiFe2 was formed near the steel matrix at 950 and 1000 °C. Subsequently, the nanoscale TiC particles precipitated and distributed discontinuously between FeTi and TiFe2 grains during the colling stage. The sizes of FeTi and TiFe2 grains became coarse at 1000 °C than that of 950 °C, which seriously reduced the shear strength of the clad plate. In the experimental condition, the reaction mechanism for the generation of compounds is that the TiC generation reaction dominated at lower heating temperatures, while the TiFe2 and FeTi generation reaction dominated at higher heating temperatures.