Explosive Bonding of Plasma Facing Components

The high heat fluxes experienced by plasma facing components in energy producing fusion devices would benefit from refractory metal layers on their surfaces; however, it is difficult to bond refractory metals to non-refractory structural and heat sink materials. Explosive welding is proposed to metallurgically bond the refractory plasma facing materials to steel or copper heat sinks. Explosive welding is a solid-state, cold joining method that produces a strong metallurgical bond, small interface and no heat-affected zone (HAZ) to weaken the adjacent regions. The bond is formed by the momentary high-pressure impact of the colliding materials and is typically stronger than the weaker of the two materials being joined. Thus, under the stresses of machining, bending, thermal mismatch, etc. one of the materials will typically yield before the bond fails. TPL proposes to use its explosive welding technology and experience to fabricate multi- layered, multi-material divertor target plates for fusion energy systems. Tungsten and molybdenum alloys are some of the most promising materials for plasma facing components (PFCs). Oxide dispersion strengthened (ODS) ferritic steels (FS) are considered a good structural material to back the refractory alloy PFC or water-cooled copper heat sinks. TPL proposes a best-of-both-worlds solution via explosive cladding: a solid refractory metal layer welded to copper or steel. TPL is not proposing new materials for divertor plates; rather a superior joining method using the best candidates identified for the different layers of the divertor plates. Commercial Applications and other Benefits: Bi-metallic divertor plates, made via explosive cladding, will enable successful fusion energy systems, experimentally in the near future and eventually in commercial applications. Clad plates and pipes can also be used in industrial boiler systems, corrosive processing and transport, bearings, and long-lasting gun barrels.