Studying the impact initiation radiation and temperature of polymer bonded explosives in the shock wave flow is crucial for understanding and predicting their reaction kinetics and detonation behavior. This work uses the two-stage light gas gun for shock loading, transient radiation pyrometer temperature measurement, and laser displacement interference system, to study the thermal radiation characteristics of the polymer bonded explosive/lithium fluoride window interface and its correlation with the interface pressure. This work optimized the polymer bonded explosives sample preparation method, significantly suppressed the luminous background of the wrapped gas and interface gap, and provided interface radiance data and interface temperature data. The results show that the time attenuation characteristics of the interface temperature during two consecutive impact loading processes are closely related to the isentropic expansion behavior of the reaction products, and the interface temperature reflects the temperature evolution behavior of the products at the interface. It provides a feasible technical way to directly obtained the reaction product temperature of heterogeneous composite explosives during the ignition reaction and energy release.

Utilizing first-principles calculations based on density functional theory, this study investigates the geometric, electronic, and mechanical properties of NaCl, KCl, and KBr crystals in phase Ⅰ and phase Ⅱ structures under varying pressures. The relationships between these properties and the phase transition points are explored. Additionally, the Gibbs free energy method was employed to judge the phase transition points of NaCl, KCl, and KBr crystals. The results show that in the phase Ⅰ structure of NaCl, the band gap value increases with pressure from 0 to 30 GPa. However, in the range of 30−50 GPa, the band gap value decreases, indicating that 30 GPa is the phase transition point for NaCl phase Ⅰ. This suggests that pressure-induced changes in electronic structure can be indicative of metal halide phase transition points to some extent. However, pressure-induced alterations in crystal structure, phonon spectrum, and mechanical stability cannot reliably indicate alkali metal halide phase transition points. Furthermore, the phase transition points for NaCl, KCl and KBr calculated by Gibbs free energy method are 22.26, 3.47 and 3.11 GPa, respectively.

The physical mechanism of “shock cooling” at the molecular fluid/window interface has troubled the shock wave physics community for many years and remains unsolved. There are three distinct viewpoints for explaining the cooling effect at the shock interface: thermal equilibrium between the molecular fluid and the window, extinction effect of the molten optical window, and specific shock response of the molecular fluid. This paper comparatively investigates the shock radiation and temperature variation characteristics of the interfaces between the chemically active fluid CHBr₃/the inert liquid argon (LAr) and the LiF optical window. Under the same shock pressure, the interface radiation exhibits distinct evolution features for the two liquids, indicating that the interface cooling effect is closely related to the fluid medium and its chemical activity. Therefore, the experimental results of this paper strongly support that the interface cooling effect is caused by the shock response of the fluid itself, rather than heat conduction or window melting extinction.