Effect of microstructures on ballistic impact property of Ti-6Al-4V targets

Effect of microstructures on ballistic impact properties of Ti-6Al-4V targets was investigated. The 20 mm Ti-6Al-4V targets having different microstructures were impacted normally by the 12.7 mm AP. The RHA steel was used as the back target, and the residual depth of penetration in the RHA steel target was measured to evaluate the ballistic performance of the Ti-6Al-4V targets. Experimental results show that the bimodal microstructure with thicker α platelets in the transformed β matrix exhibited better ballistic impact property than the other microstructures. The failure modes of Ti-6Al-4V targets varied with the microstructures. In the equiaxed microstructure and the bimodal microstructures, ductile hole formation was the failure mode; while in the lamellar microstructures, the Ti-6Al-4V targets failed by the type of brittle fragmentation. Post-ballistic metallurgical observations reveal that the propagating features of adiabatic shear bands determined failure modes of Ti-6Al-4V targets having different microstructures. The brittle fragmentation failure mode in the lamellar microstructures was facilitated by net-like propagating features of adiabatic shear bands, while the ductile hole formation failure mode in equiaxed and bimodal microstructures was facilitated by the somewhat regularly spaced propagating features of adiabatic shear bands.