From plasma to combustion under laser loading: time-resolved multimodal diagnostics of reaction dynamics in modified Al/CL-20 energetic mixtures

Laser loading is a critical and effective methodology for offering essential insights into the reaction dynamics of energetic materials under extreme conditions. This study systematically investigates five types of modified aluminum (Al) powders and their mixtures with hexanitrohexaazaisowurtzitane (CL-20) using a multidimensional diagnostic framework across microsecond to millisecond scales. Our findings reveal that Al-based systems exhibit a distinct multi-stage energy-release behavior, transitioning from early plasma-driven processes to intermediate gas–particle coupling and late-stage condensed-phase combustion. While F and AP modulate the initial reactivity of Al through surface chemistry and shock intensity, the introduction of CL-20 fundamentally alters the reaction pathway. The rapid decomposition of CL-20 dominates initial shock propagation, whereas Al particles govern sustained energy output through subsequent oxidation. Then, a multidimensional diagnostic framework is established, linking plasma chemistry, shock dynamics, and combustion behavior. In particular, time-resolved laser-induced breakdown spectroscopy (LIBS) enables the identification of reaction pathways, revealing a multi-stage process consistent with detonation chemistry, while shock-wave dynamics are governed by early plasma-driven gas-phase reactions. Furthermore, millisecond-scale laser-induced combustion duration and burning rate characterize the secondary energy release of aluminized energetic systems, reflecting the coupled contributions of gas-phase reactions and particle-scale combustion to both the release rate and total energy output. These results provide valuable insights into the coupled reaction mechanisms from plasma to combustion and offer guidance for the design and evaluation of advanced Al-based energetic materials.