Superior Strain Rate Strengthening Effect and Ductility of a Ti-4.5Al-2.9V-3Fe Alloy under High Strain Rate Loading

The mechanical response of the Ti-4.5Al-2.9V-3Fe alloy demonstrates a significant strain rate strengthening effect and strong ductility at high strain rates (3.0 × 10³/s), contrary to the typical behavior of titanium and its alloys which exhibit a trade-off between these properties. Our recent studies have revealed that this unusual improvement can be attributed to a transformation in the plastic deformation mechanism, specifically from slip-dominating to twinning–slipping combination, under dynamic loading conditions compared to quasi-static loading conditions. Microstructure characterization before and after loading confirms this change in deformation mechanism. Furthermore, simulation predicts a dramatic adiabatic temperature rise in the necking region, which may contribute to strain softening effects observed experimentally. These findings provide valuable insights for manufacturing strategies and enhance our understanding of the mechanical behavior exhibited by titanium alloys.