Experimental study on fabrication and impact characteristics of PTFE/Al/W reactive materials with different molding pressures

Here we focus on the impact characteristics of polytetrafluoroethylene/aluminum/tu-ngsten (PTFE/Al/W) reactive materials under various molding pressures. Reactive materials of the density of 3.0 g/cm3 were fabricated via pressing and sintering processes. Drop weight tests were carried out to study impact characteristics of the reactive materials. Experiment shows that, critical forming pressure and compaction pressure are approximately 5MPa and 100MPa, separately, and meanwhile, the sintering cycle could enhance the strength of the material pressed under the critical forming pressure. Furthermore, reactive materials show strain rate effect on impact characteristics, and the increase of mounding pressure attributes to the transition from inertness to sensitivity of the material. Within the molding pressure range of 15MPa, impact sensitivity of the material increases exceedingly, whereas, the impact sensitivity remains relatively stable when the molding pressure ranging from 15 MPa to 100 MPa. Phenomenologically, with the increase of the molding pressure, the drop impact induced initiation flame transits from weak and unsustainable to intense and continuous. From the point of initiation mechanism, low molding pressure introduced high porosity plays negative role against the formation and growth of the hot spots in the microstructure of the material, which was demonstrated by the experiments. The conclusion drawn from this research reveals that a well pressed condition would be beneficial for increasing the impact sensitivities of low density reactive materials.