Shear localization as a damage mechanism in pore collapse

In this work, shear localization resulting from pore collapse is studied, in potential relation to damage and failure mechanisms under shock compression. Ti-6Al-4V specimens, with cylindrical and spherical pores were manufactured using additive manufacturing, and a soft catch set-up was used to enable post-mortem analysis of the impacted specimens. Plate impact experiments were carried out using a gas gun, at shock pressures of 3-8 GPa. The 1-2 mm voids demonstrated collapse, and shear bands (SB) emanating from the void surface were observed. Varying the impact velocity and corresponding impact pressures, different states of SB evolution were studied, examining also interaction between adjacent pores. Many of the experimentally demonstrated phenomena were reproduced by numerical simulations using a material damage model. The scaling of this behavior is discussed to relate to actual porosity of materials with characteristic um-sized pores. The presented results suggest evidence that shear localization around pores could be a damage mechanism under shock compression.