Rapid ranking of thermal safety realized by accelerating rate calorimetry correlating with small-scale slow cook-off: A case study of four melt-castable explosives

The lack of effective diagnostic tools for thermal safety at the early stage hinders the design of efficient explosives to meet the application demands encountering high-temperature cook-off environments. Thus, exploring the powerful tools for rapid ranking the thermal safety sequence with small dose of explosives is of great importance but remains significant challenges. In this study, we propose a novel method for rapid ranking the thermal safety sequence of explosives via the strong correlations between accelerating rate calorimetry (ARC) tests and small-scale slow cook-off (SSCO) tests. As a proof of concept, this work focuses on clarifying the thermal safety ranking sequence of two typical (TNT, DNAN) and two novel (DFTNAN, DMDNP) melt-castable explosives through multiscale thermal diagnostic tests including TGA-DSC (∼2.0 mg), ARC (∼0.2 g), and SSCO (∼4.0 g). First, the increased thermal stability of DFTNAN, DMDNP, TNT, DNAN can be seen from the rising temperatures obtained by TGA-DSC tests. Second, ten characteristic temperature/pressure parameters at the three important moments ( onset , trigger , maximum ) of ARC tests have been extracted to correlate with the thermal safety towards SSCO tests. Among the ten parameters, the temperature at trigger moment ( T trigger ) exhibits an increasing trend of DFTNAN (224.3 °C), TNT (256.2 °C), DMDMP (258.8 °C), and DNAN (301.4 °C), which perfectly matches with the improved thermal safety ranking sequence determined by bomb debris, glass debris, and flame propagations of SSCO tests. Additionally, increasing the pressure at trigger moment ( P trigger ) while lowering the pressure increment at sharp exothermic step (Δ P m-t ) mainly correlate with the increased thermal safety. Consequently, the combination of six selected characteristic parameters of ARC tests has been successfully optimized to rapidly rank the thermal safety sequence of four melt-castable explosives for the first time, which provides a powerful tool for rapid screening the thermal safety at initial design stage, showing great potentials in energetic materials field. A novel method for rapid ranking the thermal safety sequence of four melt-castable explosives has been successfully developed by the strong correlations of characteristic temperature/pressure parameters extracted from accelerating rate calorimetry tests and the thermal violence results (bomb debris, glass debris, and flame propagations) of small-scale slow cook-off tests. This study provides a promising method with small dose of explosives for rapid screening the thermal safety towards cook-off scenarios. • Rapid ranking thermal safety of explosive via strong correelations of accelerating rate calorimetry with slow cook-off tests. • Characteristic temperature/pressure parameters enable predicting thermal safety determined by debris and flame propagations. • Higher pressure of decomposition gases before thermal runaway correlates with increased thermal safety of cook-off tests.