Microstructural Change in Electroformed Copper Liners of Shaped Charges Upon Plastic Deformation at Ultra-High Strain Rate

Abstract

Transmission electron microscopy (TEM) observations were carried out for examining the as-formed and post-deformed microstructures in a variety of electroformed copper liners of shaped charges. The deformation was carried out at an ultra-high strain rate. Specifically, the electron backscattering Kikuchi pattern (EBSP) technique was utilized to examine the micro-texture of these materials. TEM observations revealed that these electroformed copper liners of shaped charges have a grain size of about 1-3 w m. EBSP analysis demonstrated that the as-grown copper liners of shaped charges exhibit a d 1 1 0 ¢ fiber micro-texture which is parallel to the normal direction of the surface of the liners of shaped charges. Having undergone plastic deformation at ultra-high strain rate (10 7 s m 1 ), the specimens which were recovered from the copper slugs were found to have grain size of the same order as that before deformation. EBSP analysis revealed that the d 1 1 0 ¢ fiber texture existed in the as-formed copper liners disappears in the course of deformation. TEM examination results indicate that dynamic recovery and recrystallization play a significant role in this deformation process.