The influence of metallic particle size on the mechanical properties of polytetraflouroethylene-AI-W powder composites

摘要

The dynamic mechanical properties of high density mixtures of polytetraflouroethylene, aluminum (Al), and tungsten (W) powders are tailored by changing the morphology of the particles and porosity. Powder composites with fine metallic particles exhibited higher ultimate compressive strength, despite higher porosity, than less porous composites containing coarse W particles with equivalent mass fractions. The mesoscale force chains between the fine metallic particles are responsible for this unusual phenomenon. Macrocracks forming in the sample below the critical failure strain in the matrix and a competition between densification and fracture were observed in dynamic tests.