Material Enhancement through Cryogenic ECAP

Warhead liner performance is greatly affected by three liner material properties, namely, strength, ductility and circumferential symmetry. Extensive work done in the area of on-axis upset forging of round bar stock to form liner plates has demonstrated symmetry of texture which is necessary for uniform geometry during explosive formation. Grain refinement of the material has been achieved through pre-processing of the blank with equal channel angular pressing (ECAP). Work done in Phase I has shown that cryogenic ECAP, performed at -195°C, followed by a controlled annealing process, can produce dramatic enhancements in both strength and ductility of copper. Increases in these material properties can provide performance increases in warhead liner penetration capability. Phase II work will scale up this technology to the production of 9-inch diameter plates for liner testing. In addition, shaped charges from cryogenically ECAP processed material will be test fired in direct comparison with production Javelin parts. Through this Phase II project, both the strength and ductility of copper warhead liners would be significantly increased, leading to greater performance in a number of warhead applications