Localization of deformation in copper-, titanium-, and iron-based alloys loaded with convergent shock waves

Optical metallography and diffraction electron microscopy were used to study phenomena of deformation localization such as crack initiation and formation of pores, adiabatic shear bands, and channels of localized deformation upon loading of cylindrical samples of bronze, titanium alloys, and steel with convergent shock waves. An analysis of structural changes in massive disks of steel and titanium alloy loaded with convergent shock waves using an axially symmetric scheme revealed a substantial difference in the deformation behavior of the steel and the titanium alloy. In the steel disk, spalling phenomena were dominating. In the disk of the titanium alloy, bands of adiabatic shear are formed, which serve as sites for nucleation of fracture. The analysis of structural transformations permitted us to suggest a scheme of plastic flows upon localized deformation, which includes three types of flow: shearing flow, stream (cumulative) flow, and vortex-like (turbulent) flow.