Plasma and Light Flash Radiant Features Generated by Al/PTFE Projectile High-Velocity Impact Thin Aluminum Target

Abstract

To reveal the characteristic parameters and the evolutionary rules of plasma and light flash radiation produced by aluminum powder/polytetrafluoroethylene (Al/PTFE) projectile hypervelocity impacting on 2A12 thin aluminum plate, the Al/PTFE projectile was obtained by the improved sintering process of the sample, which is based on the process of the traditional Al/PTFE (mass percentage ratio of aluminum powder and PTFE is 26.5%/73.5%). The dynamic compressive strength of the sample was characterized by the self-constructed split Hopkinson pressure bar (SHPB) system. Meanwhile, the experiments, enhanced Al/PTFE projectile (mass 0.22 g, size <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times5$ </tex-math></inline-formula> mm) impacting on 2A12 aluminum targets with the thicknesses of 2 and 3 mm at different impact speeds (1.95–2.45 km/s), have been performed using a two-stage light gas gun loading system combining with a high-speed camera acquisition system, a transient fiber pyrometer measurement system, and a plasma characteristic parameter diagnostic system. The electron temperature, electron density of plasma, and the radiant temperature (in the range of visible light wavelength) of light flash have been experimentally studied. The results show that the dynamic compressive strength of the Al/PTFE specimen with rapid cooling was significantly improved at the strain rate of 4000 s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> comparing with the traditional Al/PTFE projectile (the dynamic compressive strength was 32–44 MPa), which can reach more than 100 MPa. The maximum electron temperature, electron density, and visible light radiant temperature produced by the hypervelocity impact increase with an increase in impact velocities and target thicknesses, respectively.