Contrasting the effects of cold rolling on the shock response of typical face centred cubic and body centred cubic metals

Abstract

Abstract. The response of metals to shock loading is affected by a number of factors, including the unit cell and properties that affect the motion and generation of dislocations such as stacking fault energy and the Peierls stress. In an effort to increase the understanding in this area, we have chosen to investigate the response of two near ideal materials; copper as an fcc and tantalum as a bcc. We have also investigated each material in both an annealed and cold worked to 50% reduction in thickness in an attempt to understand how differences in dislocation density affect response. Measurements have been made using standard diagnostics, including stress gauges and Photonic Doppler Velocimetry as well as analysis of the shocked microstructural and mechanical response through one-dimensional recovery.

Variations in Hardness with Position In One Dimensionally Recovered Shock Loaded Metals

“…This clearly shows that the annealed material under shock loading experiences a huge amount of dislocation generation, despite the comparatively low levels of strain, due to the dislocation velocity being too low to accommodate deformation without further generation. This is consistent with the microstructural observations from both ourselves [9,10] other workers [13]. Note that cold rolled material still possesses the ability to generate additional dislocations during shock loading, although at a lower level, again consistent with previous microstructural and mechanical observations [9,10].…”

“…This is consistent with the microstructural observations from both ourselves [9,10] other workers [13]. Note that cold rolled material still possesses the ability to generate additional dislocations during shock loading, although at a lower level, again consistent with previous microstructural and mechanical observations [9,10]. The situation with tantalum is more complex.…”

“…A technique to achieve this was first developed by Smith [2] for explosively loaded samples and was later modified by Gray and colleagues [3][4][5][6][7] for use on single stage gas-guns. This work has been adapted by the current authors to study polycrystalline copper [8][9][10] and tantalum [9,10].…”