Bonding of Dissimilar Materials Using Pulsed Power

BMDO seeks development of novel low-to-no outgassing joining/bonding techniques for advanced composites. Explosive welding, employing actual chemical explosives, is a versatile process that can be used, in principle, with any two materials. In some situations involving difficult materials, explosive bonding is the only practical joining method. Typically, a layer of explosive is carefully coated onto thin sheets of "cladding" material. Upon ignition, cladding is propelled onto (thicker) substrates. Bonding occurs through a combination of impact generated heat and high pressure. Explosives present several drawbacks: 1) Few facilities exist for handling them, due to severe safety and regulatory constraints. 2) Options for tailoring explosions to particular materials are limited. 3) Their use is not well suited to high volume production. This proposal describes a process whereby an array of controlled pulsed power generated pressure pulses replaces chemical explosives. The driving pressure is generated by electrical, rather than chemical energy. The proposed innovation presents significant advantages: It is safer and less expensive. It offers programmable control over a broad range of acceleration and impact parameters. It is well suited to small custom work and most notably, large scale, volume production including comDonents based on advanced composites. Bonded laminates are widely used in the corrosive environments of chemical and petrochemical processing plants. Potential spinoffs appear in the automotive industry in high temperature engine components and in marine environments. Composite structures are desired for rocket nozzles, turbo pumps, boiler tubes, and space applications. Primary applications for refractory composites are parts for the next generation rocket-engine fuel turbine, and the next generation gas-turbine engines.