Effect of heat treatment on ballistic impact behavior of Ti–6Al–4V against 7.62 mm deformable projectile

The present study describes the effect of heat treatment on mechanical properties and ballistic impact resistance of Ti–6Al–4V alloy against 7.62 mm deformable lead projectiles. As-received plates were solution treated above and below the β-transus temperature followed by aging. The plates that were solution treated below the β-transus temperature followed by aging exhibited good combination of strength and ductility, and better ballistic impact resistance. Post ballistic microstructural examination showed formation of adiabatic shear bands (ASBs) and adiabatic shear band induced cracks. Both as-received plates and the plates that were solution treated above β-transus temperature followed by aging showed higher number of ASBs and ASB induced cracks compared to plates that were solution treated below β-transus temperature and then aged. Plug formation was observed through the ASB induced shear localization in planes parallel to the direction of projectile impact in all the conditions.

► Effect of heat treatment on ballistic impact resistance of Ti–6Al–4V was studied.
► Bimodal microstructures show better ballistic impact resistance.
► Higher resistance to ASB induced localization improves ballistic impact resistance.
► Plug formation in all conditions involve ASB induced shear plugging.