High Strain, Strain Rate Behavior of PTFE/Al/W*

Conventional dropweight technique was modified to accommodate low amplitude signals from low strength, cold isostatically pressed energetic ``heavy'' composites of polytetrafluoroethylene (PTFE)/AL/W.~ The fracture strength, strain and post-critical behaviour of fractured samples were measured for samples of different porosity and W grain size (the masses of each component being the same in each case).~ Unusual phenomenon of significantly higher strength (55 MPa) of porous composites (density 5.9 g/cc) with small tungsten particles (1 micron) in comparison with strength (32 MPa) of dense composites (7.1 g/cc) with larger tungsten particles (20 micron) was observed.~ This is attributed to force chains created by a network of small tungsten particles. Interrupted tests at the different level of strains revealed mechanism of fracture under dynamic compression.