Effect of bi-interlayer design on the microstructure and enhanced performance of vacuum hot-forged Ti/steel clad plates

In this work, TA3/10CrNiCu steel clad plates with enhanced performance were fabricated by vacuum hot-forging after respectively adopting Nb + Ni and V + Ni bi-interlayers. The Ni foil was positioned adjacent to the steel, while the Nb or V foil was placed near the TA3 substrate. The interfaces exhibited solid solution regions of (Steel, Ni), (Nb, Ti), and (V, Ti), effectively preventing the formation of detrimental intermetallic compounds (IMCs) and ensuring robust bonding between the base metals and the bi-interlayers. Meanwhile, fine-grained IMCs generated between bi-interlayer interfaces promoted the metallurgical bonding. The ultimate tensile strength(UTS) of clad plates with V + Ni and Nb + Ni interlayers were 476 MPa and 423 MPa, and the interfacial shear strength were 306 MPa and 261 MPa, respectively. While the necklace-like δ-Ni₃Nb presented as a transition zone at the Nb/Ni interface was sub-micron, the V-Ni IMC region composed of NiV₃, Ni₂V₃, and Ni₂V + Ni₃V were much thicker. The strengthening effect of the latter was further enhanced by its superior resistance to deformation, attributed to the increased volume fraction of fined V-Ni IMCs and refined V grains. Both shear fracture exhibited a mixture of brittleness and ductility, with brittleness arising from the interfacial IMCs and ductility resulting from the fractured interlayer near the TA3 side.