Jin Chen

Energetic structural materials (ESMs) are an important class of military materials due to their good structural and energy-releasing characteristics. To improve the damage effect of metal–metal ESMs with good mechanical properties, W was added to the 48Al–52Ni composites, and the effect of W on the impact-induced energy release behaviors was investigated. The results showed that the hot-press process and the addition of W did not change the microstructure and surface state of the constituent particles, leading to a stable onset temperature of the Al–Ni intermetallic reaction in (48Al–52Ni)_100-xW_x composites. Meanwhile, the decrease in the contact area between Al and Ni in the composites with increased W content resulted in the decrease in reaction heat. During the impact process, the intermetallic reaction of W caused by the Al–Ni intermetallic reaction, as well as the oxidation reaction of Al and Ni caused by the brittle fracture along the weak interface, caused the released energy of (48Al–52Ni)₄₀W₆₀ to reach 2.04 kJ/g.

Reactive materials (RMs) are usually prepared from metal/non‐metal mixed powders through hot processing. RMs are widely used in warheads since they are inert under common conditions but release massive amounts of energy in chemical reactions induced by impact loading. However, the shock‐induced chemical energy release during impact has a complicated mechanism and needs to be further explored. This work investigated the shock‐induced chemical energy release behavior of the Al/W/PTFE RM. The experimental results show that the energy release efficiency of RM in direct ballistic tests increases with increasing impact velocity (v), and the extent of chemical reaction (y) can reach ∼0.8 at v=1250 m s⁻¹. Meanwhile, we propose a new numerical simulation approach based on the LS‐DYNA software, combining the user‐defined equation of state considering the chemical reactions and the smoothed particle hydrodynamics (SPH) method. This approach can describe the ultra‐fast chemical reaction and crushing behavior of Al/W/PTFE RM during the impact process, taking into account the mechanical‐thermal‐chemical coupling effect. The relative errors of y between the numerical simulations and the experiments are below 25 %. Moreover, the simulation results also provide many details about the ultra‐fast chemical reactions. As v increases, the values of y and the maximum chemical reaction rate (dy/dt_max) also increase from 0.134 and 0.017 μs⁻¹ at v=700 m s⁻¹ to 0.882 and 0.181 μs⁻¹ at v=1300 m s⁻¹, respectively.