Shock-Induced Mechanical Response and Substructural Evolution of Ti–6Al–4V Alloy

The effects of shock stress amplitude on the post-shock mechanical response and substructural evolution of Ti–6Al–4V alloy are investigated within the impact stress range of 6–10 GPa. The reload yield behavior of post-shock Ti–6Al–4V does not exhibit enhanced shock-induced strengthening at an effective strain level even if the shock stress achieves 10 GPa. The residual substructures of post-shock Ti–6Al–4V are examined by transmission electron microscopy. Results reveal that planar slip is the dominant deformation mechanism of this alloy during shock loading pulse. Dislocations tangle and form developed dislocation clusters (planar slip bands) with increased impact stress. The lack of dislocation cells or cell-like structures, high-density twins and additional strengthening phases limits the shock-induced strengthening effect in post-shock materials. However, dislocation multiplication and tangles lead to increased yield strength and strain hardening rate of reloaded materials.