Investigation of initiation characteristics in PTFE/Al composites through confinement suppression fragmentation experiment and mesoscale simulation

PTFE/Al composites typically react and rapidly release energy when subjected to high shock pressure loading. In this study, shock compression experiments and non-reactive mesoscale numerical simulations were conducted. When fragmentation and deformation were suppressed by confinement, the material remained unreacted at shock pressures of 10.3–12.6 GPa but underwent reaction at 16.8–18.5 GPa. Microstructural characterization of recovered samples revealed their intact structural integrity and reduced porosity. The PTFE matrix remains stable under high-pressure loading. Quasi-sealed chamber test results indicate that recovered materials still possess considerable energy release capacity, but with slightly lower levels compared to pristine materials. As shock pressure increases, the melting fraction of aluminum particles in mesoscale simulations increases correspondingly, showing good agreement with experimentally observed shock reaction initiation behaviors. It can be inferred that under shock conditions, the melting of aluminum particles dominates the material ignition process, while the melting and decomposition of PTFE may require higher energy input or longer loading duration. Meanwhile, the elevated ignition threshold pressure caused by fragmentation and deformation constraints indicates that shock ignition of the material also depends on fragmentation and deformation processes, rather than solely relying on shock-induced temperature rise.