Impact Initiation of Rods of Pressed Polytetrafluoroethylene (PTFE) and Aluminum Powders

A gas gun has been used to investigate the shock initiation of rods of a mixture of 74 wt% PTFE and 26 wt% aluminum powders. The rods were sabot‐launched into 4340 steel anvils at impact velocities ranging from 104 to 963 m/s. A framing camera was used to observe the time sequence of events. At low velocity, no initiation occurred. Above an initiation threshold, the initiation time dropped abruptly from 56 μs just above threshold to 4 μs at the highest impact velocity. Several high velocity experiments were performed for pure PTFE material for comparison with the PTFE/Al rods.