Effects of three types of additives on mechanical properties and impact energy release characteristics of Al/PTFE reactive structural material

Aluminum/polytetrafluoroethylene (Al/PTFE) is a revolutionary type of impact initiation materials, and is extensively utilized in military and civilian applications. In this research, three types of additives (W, Fe and TiH2 particles) were added into Al/PTFE, and their effects on the compressive strength and impacting reactive characteristics were investigated. The addition of W particles into Al/PTFE had the highest mechanical strengthening effect compared to the other two types of additives. The compressive strength reached 178.7 MPa, 169.2 MPa and 154.7 MPa under the strain rate of 3000 s(-1) of Al/PTFE/W, Al/PTFE/Fe and Al/PTFE/TiH2 specimens, increased by 54.6%, 46.4% and 33.8% compared to Al/PTFE (115.6 MPa), respectively. The formation of elastic PTFE nano-fibers inhibited the extension of micro-cracks was the main strengthening mechanism. The composites reacted violently under high-speed impacts, and the energy release efficiency was quantitatively calculated. Al/PTFE/TiH2 specimen had the highest reaction heat and energy release efficiency (8.15%) compared to the other three types of composites. Addition of Fe powder into Al/PTFE decreased the impact sensitivity but slightly increased the reaction intensity. However, the addition of W decreased both impact sensitivity and reactivity. The impact reaction proceeded in a mechano-chemical manner, and the reactivity arose from multiple factors.