The experimental study of plastic strain localization in the AMg6 alloy under various types of dynamic loads

This study is concerned with substantiation of one of the mechanisms of plastic strain localization under high rate loading associated with discontinuous processes in the defect structure of materials. To this end, a series of experiments were carried out to study the localization of plastic strain in specimens of the AMg6 alloy subject to high rate loads on a split Hopkinson-Kolsky bar and during target perforation tests. The temperature fields generated during the plastic deformation tests aimed to identify the characteristic stages of strain localization were investigated "in-situ" using a high-speed infrared camera CEDIP Silver 450M. The values of temperatures in the strain localization zone indicate that in the AMg6 alloy subject to dynamic loads the mechanism of strain localization caused by thermoplastic instability is not realized. After testing of specially-shaped specimens, their surface relief was explored using an optical interferometer-profilometer NewView-5010 with a subsequent processing of the obtained 3D data of the deformation relief and computation of the scale invariant (Hurst exponent) and the spatial scale of the region displaying a correlated behavior of mesodefects. The results of experimental studies on dynamic loading with a subsequent investigation of the temperature fields, the study of the surface relief of deformed specimens suggest that one of the mechanisms of plastic strain localization in the AMg6 alloy under the realized loading conditions is caused by jump processes in the defect structure of the material.