Shock-induced Structural Heterogenization

摘要

Structural instability threshold under shock compression is found to determine a transition to structural heterogenization of material. In our experiments, the threshold of structural instability is determined in shock loading under uniaxial strain conditions. Two kinds of aluminum alloy have shown different macroscopic response on shock loading - the free surface velocity profiles for both materials displays oscillations at the top of plastic front, the period of oscillations turns out to distinct by eight times. The structural investigations of post-shocked specimen also reveal a difference in the mean size of shock-induced elementary cells of mesostructure for both alloy. Furthermore, it correlates with the corresponding period of plastic oscillations. The conclusion is made that resonance interaction of plastic oscillations and internal mesostructure can be considered to be the reason for beginning the structural instability and further heterogenization of materials.