Autofrettage, Cooling, and Dynamic Loading of Fiber Reinforced MMC Jacketed Gun Barrels

Period of Performance: 05/12/2000 - 11/12/2000


Phase 1 SBIR

Recipient Firm

Triton Systems, Inc.
200 Turnpike Road Array
Chelmsford, MA 01824
Principal Investigator


The DD 21 Advanced Gun System (AGS) under development for the SC 21 Ship will be required to fire at high pressures and muzzle velocity. An extended caliber barrel is required so that shipboard exit pressure limits can be met. At the required extended caliber, high specific strength and stiffness materials are needed so that the mass moment of inertia of the barrel can be minimized. Minimizing the mass moment of inertia allows a smaller barrel and generates less parasitic weight on the ship structure. Currently, monolithic materials, including high strength steel do not provide the necessary specific strength. Fiber reinforced metal matrix composite materials are required as a jacket in the barrel. The proposed program will develop a technique to swage autofrettage a metal matrix composite jacketed steel lined gun barrel. A method is proposed to overcome the low strain to failure of typical ceramic fibers used to reinforce metal matrix composite and attain the ideal autofrettage required for a long life barrel. This key development will enable the use the high specific strength MMC materials in a gun barrel jacket to take advantage of significantly improved thermal management, and signature reduction available through the use of this material. The program is expected to develop into additional applications in the DoD, including other Navy gun systems, Army gun systems, mortars, and tank barrels. Non- DoD applications include lightweight stiff gun barrels for the hunting and target shooting markets. The autofrettage process developed for the MMC material has a direct application in automotive cylinder manufacture and in the application to actuator housings for commercial and fighter aircraft.