Dynamic hardness and formation of Portevin–Le Chatelier bands during impact indentation

The effect of shock indentation on the formation and propagation of the Portevin–Le Chatelier deformation bands in an aluminum-magnesium alloy was studied experimentally using acoustic emission and high-speed video recording methods. Dynamic and nonlinear responses to shock indentation are revealed: the first include high values of dynamic hardness and local strain and loading rates, and the second - threshold and multiple nature of force and acoustic responses. It is shown that the bands of macrolocalized deformation represent a latent bulk type of erosion damage, which reduces the mechanical stability and durability of the alloy.