The Development of Gun Barrel Processing That Linearly Gradates From A Ceramic Liner To A Metal Exterior

State-of-the-art gun barrels exhibit excessive chemical and mechanical wear when subjected to the advanced requirements of rapid fire with high flame temperature propellants. Ceramic and ceramic based interior liners offer significant potential to meetadvanced requirements, but past processing of fitting inside a steel barrel creating an abrupt interface has resulted in an inability of withstanding the mechanical and thermal cyclic loads under virtually all firing scenarios. A smooth and lineargradation from the ceramic face interior to a fully metallic exterior offers an excellent probability such liners can meet advanced requirements for large guns with a greater than five inch bore. This program will investigate monolithic ceramics andceramic matrix composite, and refractory metal cermets as interior liners utilizing fabrication processing that results in a linear and smooth gradation from the liner composition to a fully metallic exterior of steel. In addition, a high thermalconductivity copper matrix composite with mechanical properties at least equivalent to steel will also be investigated as the barrel structure. The various materials combinations will be fabricated, characterized and down selected for barrel sectiondeliveries in this program and for optimization in Phase II. In addition to gun barrel applications for all gun types from 5.56 mm to 8 inch throughout DoD, materials that grade from a ceramic base to a structural metal have applications in both IC andgas turbine engines, clutches and brakes, energy conversion systems, insulations, and general wear and erosion components.