Characterization of Explosion-Bonded Ti-Alloy/Steel Plate with Ni Interlayer

A three-layered explosion-welded (EXW) plate consisting of Ti-alloy/Ni/steel was investigated. Both the Ti/Ni and Ni/steel interfaces displayed a wavy shape typical of the EXW process, which reflects the occurrence of massive mass transfer during bonding. New phase formation was not observed at the Ni/steel interface, while, according to the SEM, XRD, and nanoindentation testing, the formation of brittle intermetallic phases took place at the Ti-alloy/Ni interface. These intermetallics serve as the weakest part of the joint and determine a brittle mode of fracture under tensile stress. The tensile strength of the joint is about 300 MPa, which is determined by intermetallic phases formed at the Ti/Ni interface.