Preparation of Multilayered Composites by Hot Explosive Welding Techniques

Demonstrative experiments have been performed to get multilayered joints consisting of titanium diboride, titanium nickel, and steel by a novel hot explosive welding technique. The technique was combined combustion synthesis, which is spontaneous exothermic reaction with very high temperature, with explosive shock welding. TiNi intermetallic layer was inserted between ceramics and steel layers for relaxation of thermal stress at elevated temperatures. Obtained joints showed cohesive and strong bonded interfaces. Successful joining depended upon the conditions of time window from initiation of combustion synthesis to blasting of explosives, the kinds of materials to buffer the reflective shock waves, and a quantity of explosives. After rapid quenching test of the specimen from a furnace kept at 500 °C to water at ambient temperature, no exfoliation was observed at the interfaces. From these results, it was revealed that TiNi with pseudo elastic effect was effective to relax the thermal stress generated at the interface between different materials.