The Influence of Heat Treatment and Loading Conditions on the Structure of an Аl–Zn–Mg–Сu Shell

We present the results of comparison of the deformation behavior and the collapse pattern of hollow cylindrical shells made of an Al–Zn–Mg–Cu alloy subjected to different pre-deformation heat treatment that were loaded by the sliding detonation in two modes differing in the duration of the shock wave pulse. It has been shown that at the same power of explosives, the convergence scenario of shells made of the studied alloy depends slightly on the duration of the shock wave pulse, which is set by the design features of the experimental setup. It has been established that the phase composition determined by the heat treatment mode strongly affects the convergence rheology. It has been shown that multiple spalling is formed in an annealed shell, while a quenched shell exhibits complete and steady convergence until it forms a solid cylinder. Light optics, scanning electron microscopy, and transmission electron microscopy have been applied to study the evolution of the structure of cylindrical shells. The different scenarios of convergence are determined by the presence or absence of nuclei of brittle fracture that are intermetallic phases, whose number, size, and nature are controlled by the initial heat treatment of the alloy.