Dynamic Response and Impact Energy Release Mechanism of (Ti2Zr)1.5NbVAl0.5 High-Entropy Alloy

To address the bottlenecks of traditional metal materials such as low energy release efficiency and insufficient dynamic response under high-speed impact, this study focuses on Ti-Zr-Nb-V based refractory high-entropy alloys. By utilizing their multi-component synergistic effect, a single-phase BCC structure high-entropy alloy (Ti₂Zr)_1.5NbVAl_0.5 was developed, with a lattice constant of 3.3501Å and an average grain size of 336.7μm. Subsequently, quasi-static/dynamic mechanical tests and direct ballistic experiments were carried out. The results show that the alloy has a good strength-ductility synergy, with a yield strength of 885.2MPa. When the compressive strain rate increases from 0.001s^-1 to 6000s^-1, the yield strength increases by 123%, and the sensitivity to strain rate at low temperatures is significantly higher than that at high temperatures. When the impact velocity increases from 734m/s to 1375m/s, the fragmentation degree of the projectile intensifies, the temperature field in the quasi-closed container rises continuously to a peak value of 2124.15K, and the corresponding energy release duration extends from 5ms to 12ms. The FEM-SPH algorithm was used to reproduce the penetration temperature rise and fragmentation behavior of the high-entropy alloy, verifying the reliability of the fitted Johnson-Cook constitutive parameters and Grunsien equation of state. Microscopic analysis reveals that the energy release of the (Ti₂Zr)_1.5NbVAl_0.5 high-entropy alloy originates from dislocation recombination in the adiabatic shear band. Under high-speed impact, the suppression of cross-slip leads to dislocation saturation, which triggers local lattice instability and further causes overall structural failure. However, under low-speed impact, dynamic recrystallization can effectively delay the failure process.