The Effect of HMX Dissolution on the Crystallization and Sensitivity of DNAN‐Based Explosives

ABSTRACT

As an important insensitive melt‐cast matrix, the energetic properties of DNAN are frequently enhanced by loading high‐energy components like HMX. However, the dissolution behavior in molten DNAN significantly influence the crystallization process and the ultimate security performance. In this study, DNAN was employed as melt‐cast matrix and HMX as the high‐energy filler. By utilizing the hot‐stage microscopy equipment for in‐situ observation and sensitivity testing, we investigated the dissolution‐precipitation behavior of HMX in DNAN and its effects on crystallization characteristics and mechanical sensitivity. The results indicate that HMX dissolution preferentially occurs in crystal edges, corners and protruding parts, and its dissolution kinetics follow a diffusion‐controlled mechanism: . The dissolution rate constant K negatively correlate with the local particle concentration. The presence of HMX dramatically influences the crystallization process of DNAN and slightly dissolved HMX molecules suppress the crystallization of DNAN system, leading to a decrease in crystallization temperature, an increase in supercooling, and grain refinement. Furthermore, crack defects are easily formed near HMX particles after solidification owing to uneven heat conduction and contraction stress. Simultaneously, the dissolution‐precipitation behavior of HMX significantly improves impact safety (with the H ₅₀ of tablet increasing by approximately 1.8 times compared to powder), whereas the improvement of friction sensitivity is relatively limited. This study reveals the correlation between dissolution‐precipitation behavior of HMX and the structure‐performance of melt‐cast explosives, providing guidance for safety design and manufacturing of the insensitive melt‐cast explosive.