The influence of metallic particle size on the mechanical properties of PTFE-Al-W powder composites

摘要

The dynamic mechanical properties of reactive materials (e.g., high densitymixtures of polytetraflouroethylene (PTFE), aluminum (Al) and tungsten (W)powders) can be tailored by changing the morphology of the particles andporosity. Cold isostatically pressed PTFE-Al-W powder composites with finemetallic particles and a higher porosity exhibited higher ultimate compressivestrength than less porous composites having equivalent mass ratios with coarseW particles. The mesoscale force chains between the fine metallic particles areresponsible for this unusual phenomenon. We observed macrocracks below thecritical failure strain for the matrix and a competition between densificationand fracture in some porous samples in dynamic tests.