Effects of Shock Pulse Variables on Shock Strengthening of Metals

摘要

The effects of shock pulse amplitude and duration on the hardening response and substructure of Cu-8.7Ge, Cu, Mo-35Re, and Mo have been studied. By means of flyer plate experiments, very short pulse durations (< 0.1 microsec) have been shown to given time-dependent hardening effects. These have been related to the time dependence of plastic deformation processes. In particular, the development of twins and the sequence of twin formation leads to effective strengthening by twin boundaries. Also, twins form in much shorter times than previously demonstrated. Dislocation generation rates are at least 10 to the 21st to 10 to the 22d power sq m/s for the shock conditions studied. Laser-induced shock pulse studies gave results in agreement with the flyer plate results. It has been concluded that the results of this work have important implications for stress-time modeling and for other effects, such as dynamic fracture, or spallation. (Author)