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

TL;DR

This study investigates how metallic particle size affects the mechanical properties of PTFE-Al-W powder composites, revealing that finer particles and higher porosity can enhance strength due to mesoscale force chains.

Contribution

It demonstrates the impact of metallic particle size and porosity on the dynamic mechanical behavior of PTFE-Al-W composites, highlighting mesoscale force chains as a key factor.

Findings

Finer metallic particles increase ultimate compressive strength.

Higher porosity composites can outperform less porous ones with coarse particles.

Mesoscale force chains are crucial in the mechanical behavior of the composites.

Abstract

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