Influence of the explosive treatment on the mechanical properties and microstructure of copper

The manuscript discusses mechanical properties and microstructure of copper before and after the explosive treatment. The aim of this research was to characterize and evaluate the influence of explosive treatment which is present during the manufacturing procedure of a new type of unidirectional cellular structure. For this purpose testing of tensile copper specimens before and after explosive treatment has been performed, accounting also for strain rate sensitivity. The experimental measurements have been supported by the 3D optical deformation measurement system and infrared thermography. The effect of the explosive treatment on coppers’ microstructure has been analysed using the electron microscopy. The study shows that the explosive treatment significantly influences the global response of copper throughout the complete loading range. All specimens exhibit a positive strain rate sensitivity. The uniform distribution of principle strain in untreated specimens is replaced by strain localization which appears just after the start of the loading resulting in much lower failure strain. The observations of microstructure before and after explosive treatment revealed that explosive loading resulted in intensive fragmentation of grains that are enriched with sub-grain layered structure. Such grain size refinement is the main contributor to strengthening of the explosive treated copper.